A better move is to always call the property (not the toll-free line) and speak with the GM, FD manager or some such person during business hours.

In some countries, local fire codes and the like limit the # of people. In some upscale properties, they really don't want crowded rooms (noise) and fills property.

But, sometimes if you explain what you want and why, you can reach a deal. Unlike airlines, hotel property senior people can be much more flexible with all kinds of things and it's always worth a call.