I agree people shouldn't lie. That being said, why don't you play with people who you've had experience with before. If you don't want that happening then play with people who you know won't do things like that to you.

Anytime I join a pug, I am cautious of everyone. I don't automatically assume just because they say they are that they indeed really are. I've played with people who are great players and just have bad days, but I know they can do it. That day might be theirs. You might have had one of those bad days. I've had them before. There are also times when people have different strategies or do things another way. Like ADS T2. I've beat ADS with my statics way, but I'm not sure if I were to pug it, how they would do things. It helps for me to expect errors to happen regardless then to assume everyone knows their job and what they do.

For some reason, anytime I see "Pro Tip" it bothers me.