the thing is, this is all fairly pointless. oh noes you locked it to her car, at worst she'll go find the janitor/security who will cut the chain for her, 5 mins effort and if she doesn't want the bike why would she care.
you think that, or anything you can do will change her? the best thing you can do is totally ignore her. people that are completely moron's who you hate only revel in all the time you put into hating them. she can be a complete tit if she wants, its her life. she's winding you up because you're letting her wind you up. first day she said she wouldn't get it, 5 mins effort, bike outside, some chav nicks it probably within about 30 seconds and its sorted.
why do people think these grand gestures will change people, or care in the slightest. if she's a nasty person she will only laugh at how much she got to you, and laugh as she has someone else cut it off for her.
get over it.