In praise of blacklisting

I was displeased, last night, to see a message from loup30 crop up in a group chat.  I thought we'd seen the last of that one, but, no, s/he/it was back again.

This is the name (user name - s/he/it has one of those display names with fancied-up characters, which is another thing that annoys me) of a recurring spambot; s/he/it's modus operandi is to pop into a group chat, post an advert for a store, and then leave the group before the moderators can withdraw s/he/it's chat privileges and/or deliver a kick.  S/he/it gets Abuse Reported for spam, of course - I've done that myself, when it involves a group I mod - but seems to keep soldiering on regardless.  (Why do I keep saying "s/he/it"?  Because I have no idea of this person's real or SL gender, and because if you say s/he/it fast, it expresses how I feel.)

Anyway.  This is one of those ongoing irritations, but it highlights a problem with the group system as a whole...  Really, with a serial spambot as active as this one, word gets around, and group mods should be able to take preventative action - but we can't.  We can't, because there is no way to block a specific person from entering a group.  The only way to keep people out is to raise barriers to everyone - by making the group closed-enrollment, or by putting in an entry fee.  (Even a small entry fee eliminates the minuscule profit margin which spammers get, so they won't pay one.)

Obviously, with many groups - new-people help groups being the ones I know best, of course - this simply won't work; those groups need to be open access so new folks can join them without impediment.  So it would really help if we could blacklist known spammers and other in-chat griefers, without raising barriers to entry for the innocent and bewildered.... There's a JIRA about it, I'm sure.  But no signs of progress that I know of.