AT&T and other ISP's in the US could care less about home or commercial mining and will do nothing. At least for Bitcoin, even a top-end miner uses very very little bandwidth. Something around 15MB per-day per miner.
I would add that latency ends up being more important than bandwidth for the reason that the less latency (a.k.a ping) you have, the more reliable and more frequent will be the exchange of information/packets between you and the pool you're mining to (assuming you want to join a pool).
With a reliable ping you'll avoid having rejected shares[1]:
Rejected shares is a term for all shares that are rejected for any of the below reasons:
- Stale share - The share was submitted too late (probably because of the high latency or problems with connection). This is the only share that is expected to happen in small quantities thus it is considered normal.
- Share above target (invalid share) - There is a problem with your mining software that needs to be inspected or configured properly. It is also possible that the mining software is not compatible with NiceHash.
- Duplicate share - The share was submitted more than once and indicates a bug in your mining software or incompatibility with NiceHash.
- Other - Any other type of rejected shares usually means a bug in your mining software.
The most common rejected shares are 'share above target' and 'stale' shares.
[1]
https://www.nicehash.com/blog/post/what-are-accepted-and-rejected-shares