Sounds like a good plan although I usually put two dollar bills in the drawer till those times I am scrounging for some mad money then spend them any way, some day I will get over the delusion they are rare.

DH and I don't do surveys.
Re the #2.00 bill. I bought two, #2.00, bills for #1.00 each at a garage sale.

I'd read the survey first and then decide.

Sounds strange! Anyone can print that address on an envelope. Don't answer any questions, they are interviewing you to learn what medications etc. you might be taking so they know what is available in your home. Why would they send you money in advance? Very wierd, I think. But, that 's just my take on it. We've had phone calls that are suppose to be from our State Health Dept., they will only talk to my husband, they won't talk to me. He is hard of hearing, so that ended the conversation. Sincerely, don't give them any info about your health.

So far I have not heard from them, I tend to want to refuse, because I don't do surveys. Last one and the only one I think, was by a dog-food brand (think it was Alpo, not sure)
I was asked what brand I use, it was not theirs, next question: does it look appetizing to you? I said no, but you have to ask my dogs, they have their own opinion about appetizing - they cut the interview short LOL

UCLA Center for Health Policy Research. It's funding is a curious mixture of state, federal and private support and its purpose is to provide fodder for statistical data for researchers who pay to access it. Googleable if that is where it came from and you can read all about it.

Puts me in mind of the Neilson TV ratings. For several years running, we'd get a notice we were a Neilson family. We got the little $ incentive to participate and we were supposed to log every show we watched for X weeks. It was so funny we'd be included in a survey for television. In my occupation, the only channel I would run, all day long was local Weather.