We've been there during "Mexican weeks" as well as before. For the most part, the Royals are the same as always with a mix of families from different cultures. During Mexican weeks the restaurants are often empty or close to empty; waiters have told us that many of the Mexican guests prefer to cook in the villas. Some families bring their own maids/babysitters/cooks.
It is not uncommon to see kids running all over the place and leaving trash around, while the parents basically ignore the kids' behavior. The staff has told us that these families are accustomed to their own staff picking up things for them so it doesn't occur to the adults or kids. Several times I've pointed out the trash cans to kids who left drink cups and snack plates on the edge of the pool, and they looked at me as though I was from Mars (but did eventually throw away the mess).
Also several times families have erected large cabanas on the beach in front of the Royals (yes, I know it's federal property), and moved beach furniture and their kids' toys in for the week. I'm sure it's nice to have a shady place to sit and play, but it's not so nice for others' view.
The Royals' staff tend to be quite deferential to the Mexican guests and won't (potentially) insult them by asking them to watch their kids or move their tents.
**Note that this has been a minority of families, and most are no different than any other families - we have met some super Mexican families and kids**