I was pretty shocked when a co-working survey asked if you felt you could leave a smartphone or laptop alone. Where I'm at, you can leave these alone without fear—it hadn't occurred to me that it is a serious problem (which obviously it is and always has been)
In my area, you can leave a Retina MacBook Pro out and not expect it gone. (If you work for a company where your laptop has serious data, then of course that stuff should be on lockdown. Most people I know with stuff like that have it locked away in secure cabinets, etc and don't leave it out.)
Anyhoo, yeah students can leave a MacBook Pro Retina, walk away for coffee or to use the restroom and then come back to it. The probability of it being stolen exists, but it is tiny. (Also the culture is such that if someone took something, it wouldn't be a surprise for others to be like, "Hey! What are you doing?!" )