"I wonder if I would do the same" - Only you know you. But I suspect you already do... You own western goods? Cross Trainers? Microwaves? That comes to you by way of cheap labor. That's right some poor schmuck gets paid $10 dollars a day, lives in a dirt-floor hut, can't medicate his sick children so you could have a cheaper microwave. The difference between this scenario and the tourist scenario is only how close it is to you personally.
I often read Farang complain about the two-price system here. They complain that it's "unfair"... But considering income potential of the Farang, life is unfair. It's only the losers who complain about it.
They can deny you... Always. The question is, will they deny you?
I have been here 10 years, most of that time I have been on tourist visas... I could be lucky but I think it's more about Thai Immigration being pretty easy-going.
I think the options are a Visa or the minimum requirements for visa exempt. The requires would be something like proof of more than 20,000 baht, hotel stay, onward travel. You should already have to the first two and onward travel can be satisfied with a bus ticket.