if you open a business and don't register it, what would happen if the revenue department or business department found out?

The first obvious thing that springs to mind would be arrest for working without a work permit.

why would you want to do tha ?

why would you want to do tha ?

i don't but someone else i know does and nothing happens to him

ahhh, so maybe considering shopping someone ?

Well i for one ( if it is in fact the case ) Report him regardless. Alot of us here set up legally and pay the taxes due , what gives this person the right to think hes any better than the rest of us ?

If not ignore the above

From what I gather tb42 has an axe to grind! The owner of the business owes him money. Well, if he's a falang then he's in for trouble. If it's a Thai running an unregistered business, I guess the powers that be will have a mai pen rai attitude.