see, that's the problem - the vast majority of icons floating around on LJ *are*grabbable - people don't know something 'belongs' to you unless you say it does

if you think you have it bad, consider a friend of mine who had her default icon, which she made just for herself (& stated as much on her userpics page), stolen...the person claimed that they got it from someone else, & said that, well, they were just going to continue to use it despite just having been told it was for her personal use only & asked to cease and desist. that is just wrong.