Interesting. I have never heard of that tactic. Personally, I wouldn't do it. Somehow, I feel it will backfire. There is something to be said about having all of the information written down on an invitation on your refridgerator for you to see every day. What if a person called you to RSVP and to get the location, wrote it down, and then misplaced the paper they wrote it down on? If they aren't familiar with the location, they will have to call you back, which creates more work for both of you. I know it is annoying when people don't RSVP in a timely manner (or at all), but I feel there is a hidden message of anger for whomever chooses to leave out the location. These are manipulative, angry people who are playing games by leaving out the most important detail on an invite.
Just do what I do when someone doesn't RSVP - just call or email them and ask if their child can attend. That is all you would have to do - not so bad, right? People who don't RSVP to parties are not mean people and are not doing it on purpose - they simply have busy lives like we all do and simply forgot. Get rid of that anger and don't send out invites that don't have the venue!