I'm not sure what "tourism visa" they're referring to but you cannot legally work on any tourist visas. A tourist visa is for purposes of tourism, not for working.
Update: I arrived at Swampy yesterday and was disappointed that the Thai line is now just automated machines. They had 2 manned stations for handicapped, pregnant women, etc. I even asked an officer there that if I am an expat, do I have to queue in the foreigner line and he said yes and pointed it out to me.
Several times I've done visa runs to Poipet, they stopped our van and checked everybody's passport. I thought this was standard for all routes to the common border areas for visa runs?