One thing we Muslims should do at these places where we are allowed to pray: Find out who is incharge of the religious services, the person who oversees the activities for the prayer room even if its just your boss at work then get a small "thank you" card and write a nice note in there "Thank you for providing a room for me to offer my prayers I greatly appreciate it." It will cost you a dollar or two, its a small gesture of appreciation but it goes a long way and it further makes it easy for yourself and other Muslims or Muslims who will be hired there in the future to offer salaah. It also gives the non Muslims an indication of just how serious we are about our prayers and what kind of relationship we have with our Creator. They will offer you their cards to make dua for them.