I have seen it done on a friends Disco, and they way he fly's around they would have given up by now, but they seem ok, but it all depends on the welder that did the welds......
Just reversing the entire wheel is not safe, as mentioned. The reason is that there is a raised bit formed in to the wheel that deforms when you tighten down the lug nuts to keep them tight. Sort of like a lock washer effect.
If you reverse them that effect doesn't happen.