How open is Dropbox to remote work? A lot of places of work "allow" or "tolerate it," but it feels hard to use this working mode for a consistent period. Working from home often has the same stigma as unlimited vacation days--you can do it, but it's often frowned upon...
I think that stems from the many people that "work from home" only to take their cat to the vet, get their car washed, go to the dentist, and pick up their dry-cleaning. Most of the time whenever I hear the term "working from home" I immediately assume they will not be home and will not be working.
I think it varies considerably depending on the company culture- in particular, how remote-oriented the company is. (Yeah, I know that sounds buzzwordy, but hear me out.)
At "remote friendly" companies I've worked at in the past, most people were in the office at least 80% of the time- and because of that, there was sort of a general mindset that if someone wasn't in the office, they "weren't there"... which lead to the same sorta assumption that you mentioned.
On the other hand, at the place I'm at now, I would guess that less than half the company are in the office on any given day. This leads to an amusing inversion of what you're talking about, because if a normally-remote colleague needs to come into the office, it usually means they won't get as much done that day, because of the overhead of travel time! :P
This confuses working from home with work-on-your-own-schedule/core working hours.
At my current company, when I work from home, I'm expected to be working and available from 9 to 5. At a previous company, you only need to be available for a specific time interval during the day, otherwise you can work anytime you want.
