No, you legally cannot do this. Work means any kind of work, and work is not allowed under B1/B2 or VWP.
Does the government bother with this.
Yes, if you are caught doing this you will certainly face deportation, and therefore a ban on visiting the US for a long time. If you are eligible for VWP you will lose that eligibility. Even if you are not banned you will face huge difficulties in ever visiting the US again.
You may get lucky and not be caught, but comparing the benefits (getting a small amount of money) with the possible penalties (being unable to visit the US for a very long time) it's not worth it.
By the way, the term 'immigrant' usually refers to someone living in the US for a long time. If you are on a B1/B2 or VWP you are a 'visitor'.