Supporting it only really has the ability to annoy and little else. Someone wants to annoy me? Send that character a few dozen times in private messages. Yes it can be turned off but if everyone has to turn it off then it's a useless feature. Yes it can be stripped on excess, but it wouldn't require many beeps to be annoying. Just one every few minutes would be enough. You compare it with colours but it's not the same. Colours have the ability to emphasise or decorate text, with flooding as an annoying side-effect. A sound effect has the ability to largely annoy people, with maybe one in a thousand making any use of it whatsoever. I for one would hate to see BELs flying around IRC from people trying to get attention because they assume other people have this turned on. Sorry but I can't see this 'feature' having anything but a negative effect on IRC as a whole.
If you really do want to be able to be notified by people then you should just script it in a form like CTCP PAGER or similar. At least with a scripted version you can control who, where, and when someone can get your attention a lot more strictly.
