Before a hotel is approved a team of 7 or 8 people go out to the property to look at such things as fire safety, security, hygiene, general standards etc.
After this has been done a representative from one of the TUs goes out (one from BALPA, Amicus and BASSA) to do their own survey. Generally the TU reps do not go into the above aspects in such great depth and take it that the fire safety/security/hygiene people have done their jobs properly.
The contract does not specify smoking or non-smoking, especially since a number of US hotel chains have gone completely smoke free this would be a big problem for sourcing rooms if it did.