Gypsies at carnivals and market days
I don't want to make any disparaging remarks about gypsies because many of them are good people and make an honest living. I will just give a cautionary warning about gypsies who sell their wares at market and run carnival rides and games. Some of these folks are on par with the shady "carnies" in the United States who will take the opportunity to rip you off. Just be aware of your surroundings and you should have no problem since they generally aren't overly aggresive. For sure you shouldn't NOT go to carnivals, in fact you would be doing yourself a great disservice by not going. Carnivals during summer are one of the great joys in Spain. It's a fascinating experience to observe the generally reserved Spanish let their hair down and get crazy. People in Spain REALLY know how to party. Go, have a good time, but be sensible.