You don't get banned just because you logged with Tor. Actually, in 99% of the cases, you will never get any account banned just because you logged with a specific IP.
What can happen is: if you try to create an account (not login) with an blacklisted IP, you may need to pay a small one-time fee to "unblock" the IP. But you will be able to login normally afterwards.
For reference:
You won't be automatically banned if someone on the same IP is banned. IP addresses are pretty poor identifiers. In certain countries it is very common for different people in the same general region to share IPs a lot, and even two veteran forum users in the same US state are quite likely to share an IP address somewhere in their IP history.
But if you evade a ban, your alts will eventually be found through manual investigation.
