Crime and Personal Boundaries
Crime, especially theft was very common when I lived in Guayaquil and Milagro and other places on the coast. The way the police handled thieves who they caught was also very disturbing. Not much oversight there, they pretty much handled thieves the way they wanted.
Also, ordinary citizens who catch thieves have their ways of dealing with them. I'm not going to share the graphic details of things I witnessed 1st hand, but it's not a good idea to get on the wrong side of law enforcement in Ecuador.
One other thing to watch out for is that it's so common for people who you get to know well to ask you for favors. I'm not talking about small favors like, "Can I borrow a dollar?" A lot of people have no problem asking you for huge favors like, "Can you help me get in to the United States?" or "Can I borrow your car?"
I recommend you become friends with everyone, but keep some distance there. "Amistad con todos, intimidad con nadie!"
Don't use the "Tu" form with people unless you're willing to do serious favors for them and their family and extended family. Otherwise I recommend you use the "usted" form with everyone. This is not a guarantee they won't ask you, but they don't have the same social boundaries as in the United States.
One more thing, most people in Ecuador don't speak more than a word or two of English, so knowing Spanish is essential!