Logging someone else's google account on my Andoid device

Question

Earlier today I had to add someones's Google account to my Android phone, to help them with something. My phone is a Samsung Galaxy S7 with the latest Android version, not sure if this is important. Anyway, I helped them and then immediately removed the new account from my device, the whole thing took 4-5 minutes at most.

Now, I know that when adding a new account Google tries to download things like contacts from the new account to the phone, but does it also try to do the opposite? I mean, upload any information from other existing accounts on the phone to the new account?

The other person does not have my login details and I use two factor authentication.

Answer 1

Google products will not try to merge two separate accounts even if it is signed in on the same device. The only way to transfer data between two accounts is via exporting from one account and importing to the other.