I'm not sure if you meant it that way or not, but you've identified the REAL problem in what you just posted.
The problem (as I see it) isn't with the touts. They're just trying to get some $$$, along with everyone else in Patong. However, if the bar was all set to charge you 300 baht, then it's obvious that the bar is ALREADY working with the touts.
Get the bars to change THEIR policies, and NOT pay the touts, and there won't be any more touts.
(Of course, if enough patrons come into that bar and gladly keep paying 300 baht for beer after beer, the bar owner's likely to think the touts are providing a boost to his business!!)
Several people here are involved with running bars in Patong. I wonder what they'd have to say about this? I'm guessing they know a lot better than most of us as to what's really going on.
(Think about it though - using your experience as an example, if these guys are usually getting 150 to 180 baht for every customer they bring into a bar, no wonder there are so many of them!!!!)
(...and before someone dumps on me for "defending" the touts, I'm not defending, just explaining. If you get bugs in your kitchen, the bugs are not the problem - the real problem is not keeping the kitchen clean, which is why the bugs are attracted to it. Same thing. Best to prevent problems beforehand, rather than have to deal with them later on.)