Chiefly about when inflicting an involuntary shape-shifting. Even when they learn to control it in due course, they will have to shift back regularly or lose control.
On the other hand, it will let them escape bad situations in their new form.
Except that she's not sure she can accurately pinpoint which ones are actually in bad situations, let alone ones grave enough to merit such escape. And she might be sloppy on her own, but her current living arrangements are with people who will mind very much indeed.