Traps behind walls

Tubs and showers and sometimes washing machines have their traps hidden from view and are not readily accessible for service or repairs. But what about sinks in bathrooms and kitchens that are behind the wall, obviously used daily more often than the other traps and more prone to clog etc. - is this a defect or even against ‘code’ or modern plumbing practice ?
Obviously we can not determine if a trap is present but how would you write it in your report.
‘Unable to determine the presence of a trap for the – sink since none is visible under this sink. This may hinder repair or cleaning of a clogged trap. Recommend a licensed plumber verify the presence of a proper trap’
I came across this at 2 sinks in 2 different rooms at 2 ends of the house. No smell of sewage gas. Im sure there there is a trap for each but dont want to make that solid determination.
Your thoughts appreciated.

I really would like to see a photo of one of these sinks. Where does the drain go when it transitions from the tailpiece? Are you sure that you’re not seeing a bottle trap there?

Drains either need to be serviceable via a cleanout or via the trap (for sinks that typically means the trap needs to be removeable). Drains which employ slip joints need to be accessible. Most tub drains don’t use slip joints anymore so you don’t see access panels like the old installations had.

A sink would require an accessible trap or a cleanout (I would call out any sink which did not have an accessible, serviceable trap). If the sink has a trap which employs slip joints and is not accessible, its a defect. If the sink has drain assembly without sip joints, it may not be considered serviceable.

I do indicate when tub traps are not accessible, as information, because I cannot inspect them.

Know your state sop.

In Indiana defect is defined as an installed system or component that is in the inspector’s professional opinion that is unsafe or inoperable. Code has nothing to do with our defects.

What does New York say is a defect?

Here ya go , long pipe also a concern - kitchen sink.

Write it up for no visible trap. It’s wrong.