Question: is there a noun in the English language for a person who treats my personal property that she has asked me to lend her, worse than she treats her own personal property?

Case in point: this afternoon I saw my neck badge strap that my roommate asked me to loan her so she could attach the hook end of it to a small purse of her's and loop it around her neck, on the floor in the kitchen. This wouldn't have caused me any great concern, normally, but the fact that the kitchen floor had been flooded the day before by raw sewage that originated from our upstairs neighbor because the sewage drains had become clogged. Thus my neck strap has become contaminated by the effluent. Her purse was still attached to the strap so I assume that she'll no longer use it and I imagine it will wind up in the trash. However, will she return the strap to me as I asked her to do at the time I loaned it to her, or will it also wind up in the trash along with her purse. Chances are it will be thrown out, without her ever mentioning anything about it.

She could have avoided this situation by simply unhooking the purse from my strap, but she has such little respect for myself and my belongings, she has decided to flaunt her disrespect by making sure that I would see it on the floor, before she eventually throws it out. I know that these sorts of straps are inexpensive and can be purchased for one or two dollars, but that's not the point. The point ought to be that she treat my strap with care and return it to me in the same condition, if not better condition, than what it was in when she borrowed it.

The only consolation for this abuse of property that I have loaned her is that it provides me the opportunity to refuse any future requests that she is bound to ask me when she wants me to lend her something of mine. I don't care if she thinks I'm being trivial, the point is, she could have returned my property, but she didn't. Therefore, why should I trust her to return anything else of mine that I may have loaned her.