This applies to the idiots driving here in Victoria as soon as the snow hits.
Since moving here I've starting thinking that people blow red lights just to see if they can.. In good weather and in bad.
Back to the topic at hand though, I think the best advice was already given: assume people will do something stupid, adjust accordingly in case they do. If they don't, great, if they do, at least you're ready.
The only blame that can be put on you is that you didn't anticipate her stupid action. Don't lose any sleep over it.
Being cheap is OK. Being a clueless sanctimonious condescending douchebag is just Vlad's MO.