Probably won't amount to anything for just a few days, but it might - best to just do it, it's pretty painless.

Nothing happened and I didn't register.

Just because nothing happened doesn't mean you shouldn't do it. If a lot of foreigners have YOUR attitude it will make it worse for us in the future. "When in Rome do as the Romans". Why fuck it up for the rest.

Problem with nonregistration: if you don't register and you are burgled, the cops could well ignore your problem - "Hey, you're not supposed to be here anyway." My first year or more here I didn't register, my attitude being that having other people keep tabs on me is their problem, not mine. But this about possibly burglary etc. was pointed out to me by a friend and makes sense, and since then I've registered. It's easy. I also knew a guy who didn't register for a week or two who then had trouble getting a visa extension.
But I wouldn't worry about any effect DaWei's nonregistration will have on anybody else.