istanbul-kid

I just bought a used RX300 at 49K, and the transmission started to become erratic, usually in the mornings when the car is cold. The dealer says should do a fluid flush at $299, if it doesn't work and gets worse then they'll replace the transmission under warranty. I cannot figure out the benefit of spending the money when I am not sure whether it will solve the problem. Any advise? p.s. do you think it is unsafe to drive it with erratic transmission? Thanks.