I think the main issue is those who don't shovel at all. There are a few houses near me where that is the case, I suspect they are houses where the landlord lives elsewhere. There was also (two? snowstorms ago) a house a block away from the Brown school that hadn't shoveled by the time the schools had re-opened. This was a bit of an issue on school mornings. At least I haven't had to worry about that for a week, and won't have to again until the 23rd.

They need a set-in-stone policy so that they can enforce something, but the vibe I've been getting is that it only gets enforced when neighbors complain, which most people aren't apt to do so long as the house appears to have put in a good-faith effort to let pedestrians pass without risking their necks. I'm not saying it doesn't matter what the law says, but common sense and logical flexibility are really hard to write into these sorts of things, so doing it on the enforcement end is probably the best solution.