Do they pay the people they bring in for focus groups?

On the most recent episode of Inside Jokes, they had the calling fake names in a waiting room challenge. One man's face was blurred, and the pop-up said it was because he was angry there wasn't actually a focus group. I took part in a focus group a few years ago that paid $250 for the day. I took the day off work to do it, and most of the other people there either had done the same or seemed like they were hard up for money and trying to do odd jobs like that to make money, so I can understand people being annoyed if they took a day off and lost pay for that day in order to come to a focus group that they were supposed to be paid for, and not getting paid. On the other hand, if you pay people, don't they have to be credited as actors? So I wondered if they reimburse the participants in any way.