Yes.

This happened to me.

I made an account, not using a phone number.

I then did not use it, for something like a month.

I posted - and the account was suspended, I was emailed, "you have violated our T&C, please provide your phone number to validate your account".

I may be wrong, but to my eye, they were attempting by deception to trick and force users into handing over their phone numbers.

I explained I had no phone number, and I had not posted at all, so it was hard to see how I had violated the T&C, and the account was unfrozen, and has been fine since then.

Exactly. This happened to me multiple times. I even had accounts for some of my side projects with phone numbers that got suspended.