The answer in general is "most likely." With Malaysia, I'd increase that to a certainty. Sure, not all properties are the same but I've found Asian hotel staff to be quite attentive and within a day or two they would notice you're no longer there. At the GH KL, staff came and found me in the lounge at dinnertime on the SECOND day that I had kept my "no housekeeping" decal up, just to make sure that everything was ok. So at this point it had been less than 48 hours since I last had housekeeping come through (they did a turndown which I wasn't expecting). Anyway, that's just one example.

It's not that the hotels would complain, but they would probably cancel the rest of your stay and issue no refund. This happens in the US all the time too, I just think there's a better chance the staff wouldn't notice as quickly in the US. There's also a very small number of properties that have been discussed a few times in these forums that have told guests they do not care if they leave. So all-in-all, YMMV, but I'd feel confident in saying you can probably get away with tacking on an extra 2 nights...maybe 3. Beyond that you are most likely going to get caught AND you'll be risking too many points/cash to make it worthwhile imo.