Not really. Anyone can host any image they want (within ImageShack's size limits, of course) on ImageShack. Even if the pic was posted by someone else on another site/forum, we don't have to worry about stealing someone's bandwidth, because it's ImageShack that's hosting the pic itself and not that person's website/blog account. Remember that ImageShack is a free, PUBLIC image hosting site. They earn/"build up" bandwidth via the ads they run and in turn, they simply allocate each pic that gets uploaded onto their servers a certain amount of said bandwidth. Once an image's allocated bandwidth runs out (which depends on large it's filesize is and how often it's viewed), the image simply expires.
Now if you had been doing it with a pic that was being hosted on someone else's personal PhotoBucket account or on someone's personal website/blog, THEN that would be definitive hotlinking as the bandwidth would be coming from a person's personal website/blog account.
I picked up a pair of IXA Caliburs since they are on sale. After seeing the Trigger Magnum I have this strange urge to pick up a pair of those as well... too bad they probably won't be as cheap as the Calibur.