I can't vouch for the SB2 but my Surface Book (1) has suffered 3 or 4 falls from hip height to hard floor, luckily every time it happened was inside a $20 ProCase like this one ProCase Amazon Link
My Surface Book has gathered all sort of scuffs, scratches and dents in it's body, but fortunately the display and all hardware components still seem to be working fine (as far as it goes for a 4 year old device). My wife also dropped a glass of water on the keyboard right where the "Escape" key is located, which means it probably got inside the vents onto where the dGPU, fan, etc. is positioned. I was able to act quickly and detach the display, and drove back home with the wet keyboard upside down, then I placed it on closed room with a dehumidifier overnight. It works flawlessly up until right now.
So in my personal experience I would say the device is pretty tough, but it might not be the case for everyone. There are a bunch of other issues that do not involve mistreatment, such as bulging batteries, display tint blotches, keyboard key caps broken (my Ctrl Key is split in half with normal use), rubber feets getting unglued, etc.
I love this device and I only want to upgrade to this series (SB3 or maybe 4 down the line)... but it is far from perfect.