Why should mIRC trigger an event beep when there's nothing for the user to see? /haltdef stops event beeps from occuring for other events, such as on NOTICE. The behavior is inconsistent. One of them must be wrong. Let's apply Occam's razor here and go with the simplest option. There are basically three ways an event can be handled. First, the default options (no script). Second, selective replacement of the behavior of an event (say, for example, on INVITE matching only certain channels). Third, replacement of all instances of an event type (on INVITE for every channel). If the user writing the script wanted to replace behavior for every INVITE event, then they could use the mIRC options to turn on or off the event beeps. If they want to selectively replace behavior, then why should they have to modify the behavior of all other instances of an event (not just for the channels they are interested in catching; trigger the beeping manually, having turned off the beeps in options)?