Sometimes yes, but usually not at a mass range level except in extreme circumstances.
The block in this case appears to be this one: https://meta.wikimedia.org/wiki/Special:GlobalBlockList?targ...
In that specific case, logged in users are still allowed, however you cannot create new accounts when visiting from that range, so you have to already have an account, or go somewhere else to create one.
The error message blocked users get should link to https://en.wikipedia.org/wiki/Wikipedia:Advice_to_T-Mobile_I... with more info on how to still edit.
