Sort:  

I'd suggest you only welcome the users, who used the tag for the first time.

I personally find these bots extremely spammy and annoying, but I guess it's your choice ...

Just remember, what happened to @wang ...

Yeah I took a look at that user, and I agree some bots are very spammy. I've made these kinds of posts to look at user opinions about this. I definitely take every single comment as advice.

I'll implement some sort of checking previous posts to check for the tag. Thanks for your advise!