Hi Sjoerd, that snake was a wild one that was likely displaced by the tropical storm (Fernando) that blew through here last Sunday. This happens quite a bit when there is flooding. During hurricane Karl, a couple of years back, a poorly run local alligator farm was destroyed and all the stock got loose. At first, they thought people would capture and return the alligators, yeah right!
Finally, the offered a bounty and then everyone became an alligator hunter.
One of the gators was found outside the Bimbo bread plant here.
People pretty much do what they want as far as animals and anything else goes. There are laws which are only enforced for political reasons. Private zoos are quite common among the bored wealthy elitists. From time to time, an animal or two gets loose, it usually ends up shot or killed somehow during the capture. Mexico is fairly strict on importing dangerous species but doesn't have a lot of success.
The bird problem is tragic. I have often seen, in the Tuxtlas, the capturing of birds and then the sale in the local markets. They use very fine nets and generations of families are experts in trapping birds.
Ask the Mystery Rider some time what he thinks about neighbors with avian pets (pests?)! LOL!