No matter how through the cabin stewards are, its always a possibility that the bugs can be missed. He would have to have a magnifying glass to inspect the whole stateroom(s). I don't think he has the time to do that.
Its a fact of life now that those bugs are out in full force. Cruise ships are no exception. I did report the incident to the hotel manager on board. The rest of the cruise was a nightmare.
Since those bugs do hitchhike with people I was afraid that I would bring them home with me.
If I cruise again, I would keep all my clothing etc in zip up plastic bags. Purchase hard shell luggage and keep it off the floor and closed.
I always say where there is 1 bed bug there are thousands more.. Be vigilant while traveling whether on cruise ships,hotels etc.