If you are planning to leave in 30 days, you may as well enter visa exempt. That gives you 30 days. Then you leave, and then you can reenter for a NEW 30 day exemption. Note you can extend the 30 day exemptions by 30 days at immigration.
Also, if you have a return ticket say 6 months later, the airline may not care as much, since they don't have to house you, just transport you back on the next available flight. You may have paid for a business class return, but if you are sent back, they can put you in a middle seat in row 59.