Sure, but I still have to design for random segfaults on memory writes. I guess I could write to all newly allocated pages and get a little more assurance that the allocation worked. I could still be whacked by a deduplicator, though unique writes would help.
I think when you run out of physical memory & swap, there's a bigger issue at that point. Or that's what the designers of overcommit decided.
OOM killer sends a SIGKILL. Writing to all pages will work for ensuring you actually got the memory. What a pain though.