I always bring a couple of pairs of linen pants just in case but my go to dinner outfit is a pair of nice linen shorts, a Cuban shirt and nice sandals. I have never had any problems with wearing that.
There are a total of 5 restaurants and two of them you require reservations for the Asian and the Italian.. the Italian is our favorite adds a spark of romance to the trip. Soft lighting, candles on the table, it has a water feature. I find the staff there to be tops and they do an after dinner drink called a sexy coffee. They coat the rim of your cup with sugar, and of course it has alcohol in the mix. Part of the show they light the alcohol and drizzle it down a spiraled peel of a citrus fruit and into the coffee.... well worth it.... and if you partake in any of the theme nights then you're dressing up on vacation. LOL.
Here are the theme nights for November: http://www.cancuncare.com/forum/temptation-resort-cancun/33343-november-2015-theme-nights.html
They are fine with nice shorts and shirt. If you want to dress up more that is entirely your decision, as it is mine not to. In all honesty what you wear to supper will have zero effect on my enjoyment of the food and company.
My husband usually wears a collared shirt, nice dress shorts, and closed toe slip-on shoes (Sanuk brand or similar). And he's never had a problem at the reservation restaurants. He stills looks nice and 'dressed up' but isn't dying of heat by wearing full pants. Linen pants are a nice option too. I like him to put in effort but don't want him to be overdressed and therefore be hot/uncomfortable. I always get very dressed up but am usually wearing something pretty revealing/sexy so it's not like I am super 'formal/dressed-up'. I might be the one feeling out of place if he were to get dressed up in more formal attire than a nice shirt/nice shorts.
I've never had a problem getting into any of them with Tommy Bahama shorts and shirts. That being said I do have some linen pants I wear occasionally but if it's really hot I'm in shorts.
Found where I said this before: As far as the attire, Elyse is pretty much all done up and in a dress. I normally wear a long sleeve button down shirt with the sleeves rolled up, or a collared short sleeve. There have been times that I have worn a nice fitting solid color v-neck tee, or plain black tee, but they are nice looking, and not like a causal tee shirt I would wear during the day. Sometimes I wear dress shorts, sometimes I wear linen pants. If I wear shorts, I will normally have on nice sneakers(not athletic sneakers, but causal shoes). If I wear linen pants, I wear flip flips. (I am not bringing work dress shoes on vacation, period). Also, I am generally wearing a nice watch. Pairing some of these things together makes them appropriate, but I would never wear the tee shirt, shorts, and flip flops together. If you have sense of style you know what's what. Now I have seen many others not dressed up at all. I question why they are allowed in, but I couldn't really care less. I guess my initial reaction is "O look this dude didn't have to get dressed, but I did, wtf!" But then I just look across the table and see Elyse all dressed up, so I would feel pretty stupid if I wasn't on the same page as her.
What is the "watch" thing you speak of in this day and age of smart phones? lol Oh, you must mean an iWatch We were just discussing the demise of the mans watch at work the other day. I do miss them as a piece of jewelry but they serve no functional purpose now.