As an enthusiast, what are your thoughts on people making requests during a cuddle session? Are cuddlers allowed to tell you what to wear?
No.
Read the sticky topics at the top of the professional cuddling board, starting with the first post in each case.
Enthusiasts making clothing requests of other enthusiasts would be really weird. People may tell you that it happens, but the reality is that that is creeps testing the boundaries of potential victims.
Clients making requests of professionals is slightly more understandable, but is not acceptable with the exception of genuine requests for reasons such as allergies. These are framed in very different terms.
Clients may express a preference, but it's up to you what you do about it, if anything. For example, a client may say, "I like as much skin contact as posssible during cuddling, so if it's ok with you I will wear a tee shirt and shorts. If you'd like to wear something similar that would suit me, but obviously if you prefer long sleeves and legs that would be a great alternative."
Tagging on to what CuddleDuncan said, if someone does make a request due to allergies - if it's not one of the most common ones I would suggest looking it up. The most common ones are: wool, polyester, scents/dyes in detergent & softener, leather tanning chemicals, nickel in metal zippers/buttons/snaps or jewelry, and latex/elastic/rubber.
Usually people who are genuinely allergic will be happy to offer alternatives and absolutely will not care if you're fully covered so long as you're not wearing their allergen. If the person is pressing you to wear a specific item of clothing, especially if it is more revealing, that is a red flag.