Come on man. The guy has a Go Pro and an entry-level Canon cameras. Who are you to attack him for this? Honestly, if a 13-year-old is into video/photo, I think this gear is money well spent.
And seriously, top of the line = Canon 1DX, Nikon D4. Stop telling people that buying an entry-level camera to enter into photography is "a bit much". It's bullshit advice. A beginner is supposed to begin with a beginner camera, and the t2i, t3i, t4i are Canons beginner cameras. Period.
To the OP: I would never leave any electronics behind in the ski resort. A GoPro fits in a jacket pocket, so you can take that on the mountain any time. A DSLR requires some planning. If you are skiing/shooting park, you will have to make a choice for the day or rotate a backpack between friends. If you are skiing powder, you will need to carry a backpack anyway so it's easier.
I personally make a choice for the day whether to take my DSLR or not. If I take the DSLR, I most definitely do not hit the park or huck large cliffs, and mostly spend my time shooting my friends. I reckon I take my DSLR 1 out of 10 ski days, maybe less. For the days that I don't want to take my DSLR, I have some smaller camera options that I can easily stash in my backpack or in a jacket pocket (Olympus PEN or a GoPro). If I need to leave a backpack behind. I use shitty old backpack with absolutely no valuables inside.