Let's take the personal out of it: what if you're a freelancer or a contractor and the email and account used (and subsequently lost access to) was your professional email and account? Something like scott@freetechnologies.com?
This whole situation makes me think I should steer clear of trello and clients that use it.
If you're a freelancer or a contractor, and you're doing work for someone who uses Trello to manage projects, you should sign up with a throwaway e-mail address. That's what I do for Github. That way, if that organization then decides to wipe the account or mess around with its permissions after I've stopped working for them, it's no skin off my back.
Personal stuff is personal, work stuff is work and ne'er shall the twain meet.
I also separate Github personally and professionally as a FTE. In most countries the company where you work has full access to your work computer, which implies also to your personal github and everything related to it.
As a freelancer they don't have access to your computer so things are different.
This whole situation makes me think I should steer clear of trello and clients that use it.