Set swappiness to a very low value, and it'll only use it when it has to. Besides which flash is generally nowhere near as fragile as it used to be. I don't know how much that extends to the chips in phones, but I'd be surprised if you could kill it appreciably faster by just having that in place when RAM runs out - the user's likely to avoid that situation because of the system slowing to a crawl more than anything else I'd have thought.

ETA - screw it, put it on an SD card. Yes, it'll be eye-wateringly slow, but it'll (presumably) stop the automatic program closures, and if you manage to fry it you can put a new one in...