I smell an old wives tale..
Firstly, Sheila had been using the PC for some time BEFORE the 80Mb HDD was installed...so despite running the PC and knowing how to save to a floppy (and hence where to put the floppy), why would she just change habits and insert the floppy disk into a gap?
Surely, if her boss needed a copy onto a floppy, she'd just do what she must have done many times before....unless she thought that the new HDD somehow made saving to a floppy a lot faster?
(PS: I also recall the times when HDD's were supplied with front bezels and brackets so that once fitted, everyone could see that YOUR PC had a HDD installed, as opposed to all the other dweebs who had maybe one or even two 5.25" floppy drives.
I was very pleased with my old 286 back then which had both 5.25" and 3½" floppies, a CDROM and a nice 40Mb SCSI HDD. Oh, and a 287 maths co-processor (which made Lotus 1-2-3 run very quickly !!).