i should say perhaps 'screen-out' would be a better term.
rather than end chat [let them explain themselvers alright], but block THEIR access to your files and screen their files from your queries. [if chat enabled and not chat-blocked, they can chat but not download your stuff - as if they didnt exist]
also if a username [used for chat - officially] were added it could ban ip address or username [for dynamic dsl/ modem users whose ip adress changes each time they reset connection]
by tweaking out the 'problems' it can imporove the rest of the network.

and by defing all zero upload slot as free loaders or anyone with upload bandwidth ratio less than x level [user definable]
if i set mine at 30% i should be able to limit those set for zero% upload bandwidth [this should be considered freeloading]