I just panda'd a HIT for half an hour that hit me ^{no pun intended} with this at the beginning:

To qualify for this study, you must be XX-XX years old. If you are not in this age group, we are sorry, but you will not be able to complete this study. We will be happy for you to participate in one of our future studies.

Really? I'm not in that age range. I should have never been able to panda this in the first place. It should have never even touched my scrapper.

You've wasted my time, and cost me money through opportunity of running another panda in your place for those 30 minutes, and this isn't even close to the first time this has happened.

If your HIT has such a brain dead obvious qualification like an age range, just set it as a hard qualification. This small time investment also helps you not have to deal with incorrect data or sorting through people who otherwise just straight up lied to do the survey anyways.

Also, abolish the masters qual while we're at it. Easily the biggest sin in regards to the qualifications on Mturk.