^ I am... *gasp* actually in agreement with you, ScanMan.
I have noticed that a "$45 oil change shop, and get a free oil change!" is actually a $15 shop, with 'up to $30' reimbursement." They also send stupid things like "Make $75 an hour taking surveys or testing products!!" When, as anyone who has done surveys knows, product testing doesn't pay much, surveys don't pay much, the real money with that end of market research is in focus groups and in-depth interviews.
They are scammy. Very, very scammy. I wouldn't be surprised if the Lasik one is actually an invite to join some medical research database and maybe get picked to be a guinea pig.
There ARE legitimate medical mystery shops out there, though. I've done dermatology, chiropractic, and dentist shops.
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Plan the work. Work the plan.