I’m sorry, but I honestly feel like this is the OPs fault entirely. It’s clear they had disabled account security on the laptop, in order for the other user who swapped laptops to add their account to that laptop. It’s not even that they didn’t enable “Find My” (which it does during initial setup, all you need to do is add an iCloud account)… he disable the password required setting to open the Mac. (Yes you can disable the requirements for logging in, but it’s definitely not the default setting) If you jump through such hoops in the first place to weaken your computer’s security, your can’t claim it’s not your fault when someone encrypts your computer on you.

I buy Mac’s specifically because for me this is a feature. I have backups. And if someone steals my laptop or I lose it, I’d much rather be out the money and the hardware and have it 100% bricked unusable and inaccessible, than have any possibility of my data getting accessed. (Not to mention making it worthless to the average petty thief).

Creating a work around, no matter how many N levels of authentication means there’s a hole for social engineering, and I’m definitely not a fan of that.

So it’s a trade off. If you don’t care about such level of security, then there are other laptop options, but please don’t ask Apple to start making their security weaker because there are those of us who want it this way.

And if you’re traveling with your laptop, put a password on it at least, and better yet encrypt it.