There needs to be some mechanism to recover your machine should this happen. It's not that much more difficult to do it on a windows machine either.
The truth of the matter is is if somebody has physical access to your machine it's not your machine anymore. They can pull out the hard drive and plug it into a machine that they have a password for and read from it if it's not encrypted. So on and so forth.
Why not install a live disc type image to USB and try out different varieties? Linux Mint offers three live images with Cinnamon, MATE, and XFCE.
I quickly found this article on installing them to USB: https://itsfoss.com/linux-mint-live-usb/
Many popular distributions offer live images so you can try before installation.