Not necessarily. You can use POP3. If you pickup often they would find precisely nothing.

Doesn't matter if you encrypt your emails, since you have control of your server. Let the fed have the encrypted data.

... at which point you might get to rot in jail for contempt until you fork over the decryption key.

I don't have a convenient link to the xkcd comic right now that talks about the difference between theoretical and practical security. ;)

To quote Spivak higher up in the comment chain:

> It's not perfect, but at least you would know you're being investigated.

Am I gonna be jailed for refusing to decrypt my files?

IANAL, but my understanding of current American law is that if the material is deemed by a judge to be evidence, and you can decrypt it, and you won't decrypt it, you can be held in contempt of court.

So they have to prove the evidence is in my emails first, and then prove my emails are on my "self-hosted" server. And I will have full control of my own data.

That's not how contempt works.

If the prosecution asserts you have evidence material to the case that you would be legally required to render and won't render it, and the judge believes you probably do, that's it; they don't have to prove the evidence is in your emails to search for the evidence in your emails. Fail to render up the emails or render them up in an intentionally-obfuscated form, and they can hold you in contempt at pretty much the judge's discretion (your mileage may vary depending on severity of crime and state law, where applicable).

(Personal observation: people of a technical bent seem, for whatever reason, to underestimate the wide swath of power the legal process has in investigating a murder case).