This is what i've come up with not to be locked out again; I carry two key chains: one in right and the other in left waist belt.
I found that the mechanism in the back door was binding and would not release with the power lock. Ended up removing the back panel and disconnecting the power lock.
The problem is usually heat related and it isn't a matter of relays sticking, but a transistor actuating the relay. The only way to fix it is to replace the master door locking mechanism.