Is it legal for married couples to stay in hotels?

Whether it is illegal for non-couples to stay in hotels depends on the specific situation. For example, when a family goes out to travel, in order to save money, it is possible that father and daughter, mother and son, brother and sister only open one room. Another example is that two colleagues are on a business trip, and only one room is opened to save money, but they really sleep in separate beds and there is no bad behavior. Such behavior may cause some criticism in human feelings and morality, but if it can be proved, it is not illegal to open a house just to save money. In this case, when the police make rounds, just explain the situation.