Either they'll flood it with honest requests, or they'll flood it to prevent honest updates. I'll let Satoshi know about PoW. He'll be disappointed, but you're probably right

Bit rude perhaps not to clarify, since you are still a PoW believer: PoW gives you no defensive advantage whatshowever. This is why it is usefull in Bitcoin, because no participant should have any structural advantage; but when it comes to protecting my stuff, i do want asymmetry, and as much of it that i can possibly get. The best example of asymmetrical defensive advantage: cryptographic keypairs. Hope this helps

You realize that a simple OTS gives you Bitcoins PoW practically for free? And denial of service on a calender server? Meh..it does not even do anything if you simply delay publishing your event until after the timestamp of that event has been mined; at which point you would have to conspire with the calender server. And if there seriously would be a scenario where that would be a plausible risk because we are dealing with something that high profile, you could just timestamp things with your own bitcoin transaction, and that would still be cheaper (and way way way more definitive of a defensive measure) than going a PoW route.