diff --git a/src/commerce/commerce.test.ts b/src/commerce/commerce.test.ts
index e580814e..fb6e1822 100644
--- a/src/commerce/commerce.test.ts
+++ b/src/commerce/commerce.test.ts
@@ -48,6 +48,29 @@ describe('Users Requests', () => {
     expect(response.data.msg).toBe('hello');
   });
 
+  it('should respect a caller-provided preferUserId of false for updateCart', async () => {
+    mockRequest.onPost('/commerce/updateCart').reply(200, {
+      msg: 'hello'
+    });
+
+    const response = await updateCart({
+      user: {
+        preferUserId: false
+      },
+      items: [
+        {
+          id: 'fdsafds',
+          name: 'banana',
+          quantity: 2,
+          price: 12
+        }
+      ]
+    });
+
+    expect(JSON.parse(response.config.data).user.preferUserId).toBe(false);
+    expect(response.data.msg).toBe('hello');
+  });
+
   it('should reject updateCart on bad params', async () => {
     try {
       await updateCart({
@@ -93,6 +116,23 @@ describe('Users Requests', () => {
     expect(response.data.msg).toBe('hello');
   });
 
+  it('should respect a caller-provided preferUserId of false for trackPurchase', async () => {
+    mockRequest.onPost('/commerce/trackPurchase').reply(200, {
+      msg: 'hello'
+    });
+
+    const response = await trackPurchase({
+      user: {
+        preferUserId: false
+      },
+      items: [],
+      total: 100
+    });
+
+    expect(JSON.parse(response.config.data).user.preferUserId).toBe(false);
+    expect(response.data.msg).toBe('hello');
+  });
+
   it('should not allow a passed userId or email for API methods', async () => {
     mockRequest.onPost('/commerce/trackPurchase').reply(200, {
       msg: 'hello'
diff --git a/src/commerce/commerce.ts b/src/commerce/commerce.ts
index f09c2524..31a2ab34 100644
--- a/src/commerce/commerce.ts
+++ b/src/commerce/commerce.ts
@@ -26,7 +26,8 @@ export const updateCart = (payload: UpdateCartRequestParams) => {
       ...payload,
       user: {
         ...payload.user,
-        preferUserId: true
+        /* default to true, but allow the caller to override */
+        preferUserId: payload.user?.preferUserId ?? true
       }
     },
     validation: {
@@ -54,7 +55,8 @@ export const trackPurchase = (payload: TrackPurchaseRequestParams) => {
       ...payload,
       user: {
         ...payload.user,
-        preferUserId: true
+        /* default to true, but allow the caller to override */
+        preferUserId: payload.user?.preferUserId ?? true
       }
     },
     validation: {
diff --git a/src/unknownUserTracking/unknownUserEventManager.ts b/src/unknownUserTracking/unknownUserEventManager.ts
index 85c4f97b..af7dbb1e 100644
--- a/src/unknownUserTracking/unknownUserEventManager.ts
+++ b/src/unknownUserTracking/unknownUserEventManager.ts
@@ -504,7 +504,8 @@ export class UnknownUserEventManager {
         ...payload,
         user: {
           ...payload.user,
-          preferUserId: true
+          /* default to true, but allow the caller to override */
+          preferUserId: payload.user?.preferUserId ?? true
         }
       },
       validation: {
@@ -520,7 +521,8 @@ export class UnknownUserEventManager {
         ...payload,
         user: {
           ...payload.user,
-          preferUserId: true
+          /* default to true, but allow the caller to override */
+          preferUserId: payload.user?.preferUserId ?? true
         }
       },
       validation: {
@@ -535,7 +537,8 @@ export class UnknownUserEventManager {
         url: ENDPOINTS.users_update.route,
         data: {
           ...payload,
-          preferUserId: true
+          /* default to true, but allow the caller to override */
+          preferUserId: payload.preferUserId ?? true
         },
         validation: {
           data: updateUserSchema
diff --git a/src/users/types.ts b/src/users/types.ts
index 79c43e2a..6dd5a0c3 100644
--- a/src/users/types.ts
+++ b/src/users/types.ts
@@ -12,6 +12,7 @@ export interface GetUserResponse {
 
 export interface UpdateUserParams {
   dataFields?: Record<string, any>;
+  preferUserId?: boolean;
   mergeNestedObjects?: boolean;
 }
 
diff --git a/src/users/users.test.ts b/src/users/users.test.ts
index 2fb189b3..01728b4a 100644
--- a/src/users/users.test.ts
+++ b/src/users/users.test.ts
@@ -36,6 +36,22 @@ describe('Users Requests', () => {
     expect(response && response.data.msg).toBe('hello');
   });
 
+  it('should respect a caller-provided preferUserId of false for updateUser', async () => {
+    mockRequest.onPost('/users/update').reply(200, {
+      msg: 'hello'
+    });
+
+    const response = await updateUser({
+      dataFields: {},
+      preferUserId: false
+    });
+
+    expect(JSON.parse(response && response.config.data).preferUserId).toBe(
+      false
+    );
+    expect(response && response.data.msg).toBe('hello');
+  });
+
   it('should reject updateUser on bad params', async () => {
     try {
       await updateUser({
@@ -52,6 +68,11 @@ describe('Users Requests', () => {
               ' If "null" is intended as an empty value be sure to mark the schema as `.nullable()`',
             field: 'dataFields'
           },
+          {
+            error:
+              'preferUserId must be a `boolean` type, but the final value was: `"string"`.',
+            field: 'preferUserId'
+          },
           {
             error:
               'mergeNestedObjects must be a `boolean` type, but the final value was: `"string"`.',
diff --git a/src/users/users.ts b/src/users/users.ts
index 46c11620..c5a30209 100644
--- a/src/users/users.ts
+++ b/src/users/users.ts
@@ -38,7 +38,8 @@ export const updateUser = (payloadParam: UpdateUserParams = {}) => {
     url: ENDPOINTS.users_update.route,
     data: {
       ...payload,
-      preferUserId: true
+      /* default to true, but allow the caller to override */
+      preferUserId: payload.preferUserId ?? true
     },
     validation: {
       data: updateUserSchema