Not Always, obviously. Until now I’ve just met one guy who lives close to the place I study .and he is nice and trustworthy, and we are good friends until this day.
But, generally I only practice with them my language and vice versa. So, even if someone lies to me it won't affect me although I always provide genuine information about myself, and if I feel bothered I don't answer, it’s the easiest way :-)
But, if I want to go further with someone in this friendship, I should be sure that he is honest towards me.
The important point is, further we advance in any relationships the more we need to be sure about his honesty.