Applying "Code Logic," the interior part of the outdoor raceway is still a wet location, so NM is not allowed. Damp location, you say? Still not allowed - I have yet to see a roll of NMC at the parts house; it's all NM-B.
(The 'dry only' limitation in the 2009 can also be used to call into question nearly every crawlspace out there).
Practically speaking? The individual conductors - marked or not - are up to the task. While the code would say 'only if the individual conductor4s are identified as suitable for a wet location, and only if you remove the outer jacket,' in practical terms I don't see the hazard.
If you really want to get their attention, apply conduit fill rules; that will have them running at least 1" raceways! I expect they'll quickly discover junction boxes and jacket strippers.
Likewise, note how the t-stat cable is run .... and have them NOT run it through the power raceways (most will then run it in with the line set).
NM is probably the most confusing wiring method, at least as far as code rules and design is concern. On the one hand, they claim it is safe, and are expanding where it may be used. OTOH, it's considered unsafe, and is the method of choice in defending AFCI requirements. Not only are there the varioua types of NM, there are several wiring methods (UF, SER, etc.) that are very similar, with different rules applied.
