Do domain transfers get authorized by snail mail or email?

[Seacrest]

Depends on the registrar, prolly.
We just did one, and had to fax a 501c3 to GoDaddy for it to happen.
Took a couple of days, but they responded via email, and then it was pretty simple to follow up online.
("simple", being a relative term, considering GD's often byzantine website.)