[xigoi]

> People can also send you unsolicited messages by replying to you or @-mentioning you.

You can deal with that by blocking them personally. No need for a guardian angel.

[lupire]

You can't block everyone bad because you don't know who they are until after they spam you. Last month I got 100 spam texts from the same sender ([Redacted] Political Party) using a different phone number for each.