OK - an opposing point of view from the grinch. Apart from legal considerations (like fire regulations) - I think a hotel has a right to be "kid-friendly" - or not "kid-friendly". To attract families with kids by letting them stay 3/4/5 in a room for the price of 2 - or by enforcing room occupancy limits. My husband and I are travelers who like to relax on the road. We want quiet in the morning - quiet in the evening - hallways which aren't used for fun and games - pools where we can swim laps - dining where we don't have to worry about tripping over little people at breakfast or finding the floor under our table covered with the debris of children meals - etc.
Regardless of how well behaved your children are - they are still children. If they are young - they cry - and they sometimes scream. If they are older - they like to watch TV or play video games 24/7 - loud - especially in the mornings and evenings when my husband and I may have other things on our minds. They resent being cooped up in small hotel rooms. They do not generally enjoy 3 hour dinners - and - if they are younger - a fair amount of what they're served at meals often winds up on the floor.
There are hotels that market to people in your situation - and hotels that market to people in mine - just like there are properties that are pet friendly/non-friendly - smoker friendly/non-friendly - gay friendly (don't know of any properties that are gay non-friendly - but there are definitely ones that are very friendly - to the extent that they discourage straight guests). I generally try to avoid properties that are kid friendly (e.g., most of the hotels in Palm Beach these days) - and I think you should respect the right of a hotel which is trying to attract a different clientele. Robyn