Certainly. We have a number of students in various faculties for whom the norm is to work one part-time job, and a whole lot are working two.
I finished my studies 28 years ago and only received about $2,500 less than what is a SSHRC doctoral fellowship today. In real dollars, obviously these are individuals who are falling behind, and they need to seek that extra employment just to make ends meet. Of course, that prolongs their time in graduate studies and their not getting out into the workforce as we would want them to.