i cant see why they would break while being removed. This is a prett straight forward process. I've done it a zillion times. Yeah, there are things you can do that will shater them Some of them take less to break than others. I find the most common mistake is trying to pry it up so it's easier to cut. That will probably break it 50% of the time.

I found that a box of straight razors, suctions cups and a few hours is the best way to go about it. just remove all trim around the window, then slow cut out the caulking. be careful not to cut the actual window as this can also cause breakage, depening on the type of glass. Then use your suction cups to bring it out. Usually a 2 person job. I've pulled them from the outbacks before w/o a problem, I'm just asuming they are made the same, as most are.

Since they seam to have problems w/ it, tell them you'll do it for $20- $50. Obviously if they cant get them out they have no use for them, right? and if you cant, at least you had some fun