My thoughts on the subject - and they have nothing to do with legality - presumed or otherwise.
I have a car that I wouldn't want to go over 100km/hr (US readers do your own metric coversion) in. However If I wanted to drive really fast, I could get another car that can handle it.
mIRC is designed to be a Chat client - which is typically a low bandwidth activity.
For all those people who want to trade/download/upload large files, they would be better off getting a programme that is designed to deal with it.
I wouldn't use MS Word to transfer large files, I would use it for Word Processing. I woudln't use IE to transfer files, I use it for browsing and replying to notices like this!.
If i was going to be transferring a lot of files, then I wousd expend a little effort to find a suitable program, not try and shoehorn another program to fit the mold.
So, to all these people who complain that mIRC doesn't handle their file trding properly - I say stiff bikkies, find another program that is designed to do that!
mIRC is good for chat - not word processing, browsing, complex scientific calculations or file-trading.
Just my opinion to add to the mix.
Cheers,
DK