This couple that was in the same train as me, left their seats to change the diaper of their little baby.
Not only did they go away from their luggage, but they left two phones and a large tablet visible and unattended for quite some time!
Nah, it can be totally fine.
I don't want to pack my entire train setup everytime I need to take a piss, especially when there is a close to zero chance that anything will get stolen.