I participate in a taste test program where they qualify you for certain studies and then pay you (and your selected K-12 institution) a modest sum to eat stuff and tell them what you think. It's fun, mostly because I like to observe their methods. And I like food. And to give my opinion.
As long as I've been a member, participation was limited to those under age 65. Just this week, I got an e-mail that they recently extended the upper age range to 85, so I sent my mom over (though she's not yet 80), because she buys food! And beverages! And she has time to go to studies in the middle of the work day! And she purchases food for my school-age children! And she has an opinion!
I always thought it was odd that they didn't care about the buying power of people who can afford to blow their childrens' inheritance at the casino.