Back in the olden days, like 1995, classmates used to buy cheaper DD floppies and drill holes into them to use them as HD floppies (the 3 1/2 floppy had a hole in one of the corners to allow the drive to distinguish between DD and HD drives).
I didn't do that because I feared data loss, yet in a recent discussion, people claimed that this was not much of an issue. Which led me to reconsider; I assume that manufacturers switched to producing only HD media, simply putting some of them into DD casings, possibly those who didn't pass as well in QC. From an economic perspective, it would make perfect sense: rather than having to manufacture two different media, the manufacturer could produce only one. The cost difference between DD or HD media would vanish over time and far outweigh the expenses saved by having to maintain only one production line.
However, someone else claimed that there is a substantial physical difference between DD and HD media, which is substantial enough to necessitate the production of "true" DD media. Therefore, people "faking" HD disks would really risk data loss.
Is he right or not?