Easy but for single-server setups also silly. If your server falls off of the net your DNS goes boom too and you have no shot of redirecting people to a landin

Easy but for single-server setups also silly. If your server falls off of the net your DNS goes boom too and you have no shot of redirecting people to a landing page or similar "oh shit" activities. Now you could re-point your nameserver records but in my experience that takes longer to propagate than a new A record with a short TTL.