I know many people who have done this. It seems they eventually got caught and fired.
As far as getting people to take the survey, I am not sure the best approach. Honestly, if I were one of those people doing that, I would not take the survey, which would leave only honest people taking it and that will give you inaccurate numbers.
I am not sure if you have a site you can put it on currently, but I would suggest promoting it on sites with a "complete survey for a chance to win" sort of thing and offer a potential reward. Other then that I think your best bet would be to reach out to restaurants, and have them give them to their servers and then they give them back to you. Just make sure you put on them that it is confidential and the owner cannot view, or fire based on results sort of thing. I still do not know how much participation you would get.
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