WWJD?

This week Ben and I stopped in at the bank over our lunch break. As we were walking down the sidewalk Ben points out: "Johanna - oh my gosh - you can see that lady's butt!" And in my mind I'm thinking she must be showing some crack out of the top of her jeans. Oh you could see crack alright....but not at the end you normally would.
This heavier-set woman is wearing a tiny short yellow cotton skirt and it is hiked up so high you can see both bum curls!!!! Really!
It was incredibly shocking and disturbing. I just froze - do I run up the sidewalk to tell her I can see her bum or just let her walk along not knowing that she's showing the whole world her rear?
I see pros and cons here:
Cons: the closer I get to her, the more hideous bum I'd have to see
This may be a new FSJ style and she may be really offended
Pros: Like ripping off a band-aid, it would be over quickly
This would likely save this woman some embar-ass-ment as she is about to head into the crowded bank

So - What DID Johanna Do? Post your best guess and I will be back soon.