[#][TikTok] 1234 is your verification code
At first I assumed these were someone accidentally or deliberately giving TikTok my phone number when registering. But if they never got the code, How could they activate the account? So why would they (or others) keep using my number? I read online that it may be a confirmation needed to delete an account. But that implies that TikTok accepted my phone number without verification. And again, if the person didn't get the code, what good did using my phone number do them?
All very dubious.
...And don't give your test suite access to the real world.