diff --git a/demo.py b/demo.py
index 1c31a2e..de1e870 100644
--- a/demo.py
+++ b/demo.py
@@ -14,6 +14,7 @@ import ids
 import imessage
 
 import trio
+import argparse
 
 logging.basicConfig(
     level=logging.NOTSET, format="%(message)s", datefmt="[%X]", handlers=[RichHandler()]
@@ -64,7 +65,7 @@ def safe_config():
     with open("config.json", "w") as f:
         json.dump(CONFIG, f, indent=4)
 
-async def main():
+async def main(args: argparse.Namespace):
     # Load any existing push credentials
     token = CONFIG.get("push", {}).get("token")
     token = b64decode(token) if token is not None else b""
@@ -146,6 +147,14 @@ async def main():
                 })
             safe_config()
 
+        if args.reregister:
+            print("Re-registering...")
+            import emulated.nac
+            vd = emulated.nac.generate_validation_data()
+            vd = b64encode(vd).decode()
+            users = ids.register(conn, users, vd)
+
+
         # You CANNOT turn around and re-register like this:
         # It will BREAK the tie between phone number and Apple ID
 
@@ -275,4 +284,7 @@ async def output_task(im: imessage.iMessageUser):
 
 
 if __name__ == "__main__":
-    trio.run(main)
\ No newline at end of file
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--reregister", action="store_true", help="Force re-registration")
+    args = parser.parse_args()
+    trio.run(main, args)
\ No newline at end of file
diff --git a/ids/__init__.py b/ids/__init__.py
index c433257..af8cab2 100644
--- a/ids/__init__.py
+++ b/ids/__init__.py
@@ -117,7 +117,8 @@ def register(push_connection: apns.APNSConnection, users: list[IDSUser], validat
     # Construct user payloads
     user_payloads = []
     for user in users:
-        user.handles = user.possible_handles()
+        if user.handles == []:
+            user.handles = user.possible_handles()
         if user.encryption_identity is not None:
             special_data = DEFAULT_CLIENT_DATA.copy()
             special_data["public-message-identity-key"] = user.encryption_identity.encode()
@@ -125,7 +126,7 @@ def register(push_connection: apns.APNSConnection, users: list[IDSUser], validat
             special_data = DEFAULT_CLIENT_DATA
         user_payloads.append({
             "client-data": special_data,
-            "tag": "SIM" if isinstance(user, IDSPhoneUser) else None,
+            "tag": "SIM" if user.user_id.startswith("P:") else None,
             "uris": [{"uri": handle} for handle in user.handles],
             "user-id": user.user_id,
         })