I don't get it either. It must be faulty in some way. It's unlikely that both remote batteries would be weak, but it's still a possibility.
Does anyone know if the lock/unlock rocker switch by the electric window switches would unlock the car? That's if I can hook something around to operate it.
Failing that, I suppose a new emergency key from Lexus is the next step. It'll be a bit difficult proving the car is mine, considering all the paperwork is still in the glove box!
If I can't get a key from Lexus, at least I can take my frustration out by smashing the windscreen with a very big hammer!