Blumpkin, wouldn't most players bet here thinking their four card low is a favorite (for the low end) over a likely bricked 3 card low?

I'm still not very good at this game, but I think check-raising seems like a pretty good play. His opponents hand obviously has limited scooping potential, so he's basically just charging him the maximum to draw to his low. If he caught something dangerous, check-raising might be a little silly, but the offsuit 7 looks completely benign.