"Wearing pyjamas at breakfast is the height of sloppiness," etiquette expert William Hanson told Sun Online Travel.
"Whilst hotels encourage you to relax and be 'at home' there are limits and this usually relates to the private areas (your room or suite) and not the public or communal areas."
A post on Quora asked: "Should people attend the free breakfast buffets at hotels in their pajamas?"
Responses were mixed. A user named Beth Goldowitz said, "Absolutely not".
"Nor should they do their makeup on the subway, or wear flannel robes to drive their children to school. And yet, we see these things all too often, because people have become increasingly casual about how they dress in public."
However, user Hatem Faheem said he didn't see a problem, "as long as you smell good and your clothes are clean."
On TripAdvisor, a user called Myflyon claimed to have made a complaint to hotel management after multiple guests came down to breakfast in pyjamas.
"In all our travels we have never experienced this before. I think it is not appropriate," they wrote.
"When I brought this to the management's attention, I was told that as long as they were dressed it was OK."
Another user, JAtlanta, responded to the review to say they were overreacting.
"As long as nobody was exposing himself, what's the big deal. Wear what makes you comfortable and stop obsessing over what other people are doing."