The fact that you have posted schedules and are stressed about being on her "list" suggests you're in the latter kind of workplace. If being tardy means leaving customers or colleagues in the lurch, or fudging billable hours, you can't really argue that it's no one's business if you slide in a few minutes late.
More to the point, does your boss simply humour her snitching - or encourage it? Snitches are only as dangerous as their audience is receptive.
Either way, the best way to shield yourself is to not let her be your primary point of contact with the boss. If you're usually on time and reliable, and you have a good relationship with your boss, the snitch will become irrelevant. You can even beat her at her own game by giving the boss a heads-up when you're running late. Ideally, your boss will either appreciate your conscientious attitude, or will confidentially tell you not to worry about it. Reasonable bosses understand that sometimes cars break down, kids can't find their shoes, buses run behind schedule.
Of course, if you're having to make those calls on more than the "rare" occasion, it might prompt you to reexamine your commuting habits. Or if it turns out your boss is not the reasonable sort, you might want to reexamine whether your employment situation suits you.
Incidentally, Crabby Patty may indeed be awful. But from the way you sort of gloss over your constant reminders about her cellphone and whatever you said that she "didn't like," I have to wonder if the annoyance is mutual. Maybe her crabbiness, schedule obsession and subversive communication style are products of anxiety, rather than malice. Or maybe this whole situation is yet another piece of evidence that installing workers in an open-plan office builds camaraderie about as well as herding rats into an open-plan cage.
- Washington Post