The rules are not clear. Every turn I can make a suggestion once I am in a room, but do I have to? Can I just end my turn?
From the rules here
As soon as you enter a room, make a suggestion.
It's very common in games rules to use the word 'may' when something is optional. The rules use the word 'may' in other places. This would mean that making a suggestion is compulsory on entering a room.
However you may not remain in a room on your next turn. (and thus make another suggestion)
You may make only one Suggestion after entering a particular room. To make your next Suggestion, you must either enter a different Room or, sometime after your next turn remain in a particular Room.
Thats not how I was taught the game as a child and we just stayed in the same room making suggestions! So I've learnt something new today.
If the question is, "Am I required to make a suggestion whenever I enter a room?", then strictly speaking the answer is yes. The rules explicitly say "make a suggestion".
However (except in the case of the first time in the game that a player enters a room) in practice you can effectively avoid this by simply repeating a suggestion that you or someone else has previously made.
And making it look like a mistake could be more advantageous than giving people the information that you are refraining from making a suggestion.