I hate when it happens to me, but love when it happens to someone else. So how about something like this

if(($line =~ /^\s*\/m(\w*)/) && ($1 !~ /^e|sg/) &&
   ($username eq 'tcf22')){
  print "Don't know how to '/m$1', maybe you meant /me or /msg?\n";
}else{
  &post_message;
}
[download]

Ok, now my serious response.

I agree with liz. Perhaps we could make it a user option that could be turned on/off.