and you cannot block someone from viewing your profile. You can BLOCK them, but they'll still be able to see your profile, you just won't know about it.
At least, I'm pretty sure that's how it works..LOL
What Kana said. People don't write "I'm an unserious fake only here to waste your time" on their profiles.
You'll know a lot of the time, eventually. But sometimes, an intelligent jerk who knows how to write will fool you, badly. It happens. That's how it is. Come to terms with the fact that it goes with this medium, and beware.
Be more concise as to what you mean by "really into BDSM" and "games".
Do you mean you want people who are hardcore (explicitly explain what you want on your profile and how far you want to go), or people who are actually serious about meeting (meet them face to face)?
You can hide your profile, but then no-one would be able to see it. You can block people from contacting you but they'd still see the profile.