Personally, I feel that too much emphesis is placed on the fact that a relay can fail. So do earth leakage relays. I replace on average 2 each week.

If one uses a good quality relay, then I don't see a problem. One should expect the component to do the job for which it was designed for a considerable period of time before malfunctioning.

If you don't trust the relay, then either install 2 in parrallell or a better quality one, but then be sure to also install 2 earth leakage relays in series just in case one of them goes faulty.