I don't see why its necessary plus I can see it causing some problems in the future. If you've sent a battle to someone and they're taking forever to respond, you can always get a mod to delete it so you can re-use the bars elsewhere. I take requests all the time for stuff like this in the
Delete Battles Thread.
The problem with giving an automatic L if they don't respond within a certain time is not everybody is on here everyday. Some people might be active, and then real life shit comes up and you don't see them on LB for a while. Should they receive an L because someone decides to send them a battle and they weren't even here to notice? Plus you'll probably have people taking advantage of that and sending battles to people that they know ain't been active since 2006. I would say NO. Its unnecessary and it would create complications.