It's better not to put too much stock into these kinds of assumptions. I'm speaking in general, not for people here, but you never know what kind of person you can run into. Sometimes when people hear I'm a Buddhist, they can find some fault with me that doesn't comply with their idea of Buddhists. They don't seem to understand a Buddhist is someone following a Buddhist path, not necessarily someone who's already knows everything about it and/or achieved all or some of the fruits of the path. So in the same way, even if you're speaking with Vajrayana practitioners, there is no guarantee that they'll be knowledgeable and so on.  