The point is that it doesn't matter at all what you think is reasonable. All that matters is what the immigration authorities in the countries you visit decide, and they can be very capricious in some of these countries.
Personally I haven't heard of anybody having trouble anywhere in SE Asia on 30-day stays but I have heard of people getting in trouble for working on 2-3 month tourist visas, often when ratted out by other foreigners.
Personally I haven't heard of anybody having trouble anywhere in SE Asia on 30-day stays but I have heard of people getting in trouble for working on 2-3 month tourist visas, often when ratted out by other foreigners.