That's actually why the torservers.net people suggest *not* using disk encryption. Having no barriers makes it much easier for the police to realize that there's nothing useful to them.
This falling over may perhaps not be preferred by operators who like to create wins in the crypto war. You want police to go get their warrants, waste their time and money, just to prove nothing upon decrypt... then you have higher recorded, thus marketable, percent of nothing found among all forced decrypt cases. Instead of closer to 100% of such cases just confirming already forgone criminal cases. Having higher barriers and costs and demonstrably less fruit ratio can make such seizures more unlikely in first place.
Can they force an operator to decrypt, if he lives in other country which is non-US and non-EU (e.g. Russia or China)?
Depends if hosting country can extradite, or threat influence at things of value such as bank accounts, travel bans, people, etc.
Does it make sense to run nodes in countries you don't live in or visit?
If poor odds or afraid of such things, the farther distant and / or opposite legally, politically, logically and physically the better.
What happens if an operator themselves is anonymous?
They lose the remaining hosting contract worth of bitcoin, get the account / card canceled, nym blacklisted, etc.
For only running an exit / relay and nothing else...
Policy / nuisance shutdowns by the hoster do happen often, nodes just move and redeployed elsewhere.
Detainer for questioning, are rare, oops, you're free to go. Raids and confiscation, are rare, and property seems to be returned. Actual arrests / night in jail / charges, are even rarer, oops you're free to go. Charges that go to court, are extremely rare. Probably no one has *ever* been convicted that we know of?
Because only running an exit / relay and nothing else, seems to be legal everywhere. (If it is illegal somewhere, then the operator is at fault for breaking that law.)
And traffic passing through relays seems to have "ISP style" legal exceptions everywhere, that even cover "torts", so long as operators are not in business of inspecting or moderating.
Which is why everything above is marked "rare".
If you know of places where... a) relays themselves are illegal or b) ISP style exceptions do not exist ... you should definitely reply with such a list.
Real problems are rare, and running relays is fun :)
Legal environments typically apply equally so once you know your environment you can always add other overlay networks / services / nodes into to the mix if you're bored or have unused bandwidth in your contract: I2P, CJDNS, GNUNet, Freenet, Pond, VPNGate, XMPP / IRC, Remailers, Crypto Currencies, IPFS, etc...