Now there are massive blocking of Twitter accounts.
Most often, block accounts when you to use mass-following. Blocks is forever!
Also do not use hashtags #ICO #Cryptocurrency etc
Be careful!
UPD
Some accounts of my friends that have been blocked marked "forever" are now unlocked
But anyway, I think we need to be careful
Thanks for the warning. It's unclear why they block for hashtags. And if it's not difficult, tell us how your friends managed to unlock, blocked forever accounts. I think many of us would be grateful for this information.