They do. Plenty of people do. The problem is that these EBS failures always propagate across availability zones no matter what Amazon says.
Do you have any evidence of this? Because I haven't seen any. And it sounds tin-foil-hat.
Because you have no hard experience of what multiple availability zones practically means in Amazon's infrastructure.
Actually, I run a load-balanced, redundant site on AWS. I ask the question because Multi-AZ (as defined by AWS) means geographically different, as in US West (in Oregon) vs US East (in Virginia) - NOT just the difference between US-East-1a,b,c,d (which Amazon makes very clear are in the same data center). That's why it's odd that Virginia's issues would affect Oregon (or any of the other AZs) Try being helpful next time and answering the genuine question instead of smarting off because you can't get on reddit.
Karl's version of Parkinson's Law: Work expands to exceed the time alloted it.