@Tomasso ************
They won't ask you about 90 day reporting at airports or land border crossings, but they will put a 90 day reporting slip reminder into your passport.
It doesn't matter to immigration at the border whether you've done it or not, as they don't handle these matters.
A different story in China - or Beijing at least. Anyone who doesn't register their accommodation with the authorities (similar to the TM30) may get denied entry on their next re-entry and is ineligible for the 7 day visa waiver for transit passengers traveling via China, en-route to 3rd countries.