Edit: Apparently they're not actually as strict as I remember, but all three definitely have some sort of a system.
Edit: Apparently they're not actually as strict as I remember, but all three definitely have some sort of a system.
I don't believe TF2 has any sort of phone number system that I'm aware of. If there is one, it doesn't seem to function very well given the bot invasion over the last few years.
I can't speak to dota 2 as I've never played it.
[0] https://help.steampowered.com/en/faqs/view/00EF-D679-C76A-C1...
It used to be that to get prime queue (or whatever it was called) you need to phone number, since the open queue was filled with hackers. The new systems still attempts to do the same, just without the hard boundary. You may end up in the hacker lobby, or you may not. You won't know.
If I remember correctly, in TF2 competitive mode and Mann vs Machine (pve) gets locked if you don't have steam guard enabled. But you still have access to casual and community servers, which are what you will usually want to play.