I was in mourning after losing a relative and refused to participate in an overtly cheerful activity.Not only was I reprimanded for it, but later heard the professor felt the need to complain to other people as well about yet another kid 'whos grandma had died'. It just so happened that my grandma had not died, nor would have I cared much if she would've had, but a much more cared for relative.
Thankfully it was quite a lot of years ago.
Many people, especially poor folks, don't do obituaries, because they can be expensive. Original death certificates are always in high demand, and people tend to not realize that they need dozens of them -- proving to a teacher that grandma died is low priority. There are other cultural factors as well. Some religions call for immediate burial, so publication of the obituary will likely lag the student's absence.
Another factor to consider is that fall exam times line up with the holiday season, which also happens to be a time of the year when death rates spike.
Given all of the other accommodations that colleges give students, I don't see the big deal here. When I was in school, I was able to get incompletes to finish coursework or take exams late for various reasons. I had friends who got ADD diagnoses from doc-in-the-box places because they found taking exams in lecture centers with tiny desks impossible to deal with. If a C student gets an extra 3 days to study, the outcome is likely the same as it would have been.
A lot of teachers have become jaded and will assume every student who brings this up is a liar and a cheat.
The problem though is that although the majority of the cases are made up to get out of exams or assignments, a small number aren't. These students, in addition to losing their beloved relative then can become very distraught to find themselves unexpectedly saddled with a false accusation of being a liar.
Because of this, when I taught, I would nod and sympathize, then say that because there had been some abuse of this in the past, they could have an extension or such only if they provided an actual published obituary from a newspaper or funeral home. Some other teachers use another method, of having a certain number of exams or assignments that can be dropped without penalty. Of course what often happens in those cases is students drop an early exam, and then later claim injustice at not getting an extra one for the deceased grandparent.