Floppy disk media density/format mismatching

I was hunting around on ebay, and I found this quite by accident. http://cgi.ebay.com/ws/ eBayISAPI.dll?ViewItem&category=4610&item=2085201851 It is an auction for some reproduction Apple Lisa system disks. The guy certainly did a good job copying the labels, but I really wonder about the data on them - the disks he used are high density floppies. I always thought that if you format a high density floppy for low density that it will work for a while, then the data will become corrupt due to the different magnetic properties of the media. I know that this is true on 5 1/4 media, I used a high density disk in a Commodore 64 by mistake once, and it didn't work very well. I also remember back when high density 3 1/2" floppies were pretty expensive, I used to buy low density disks and drill holes in the other corner so I could reformat them for high density. It worked just fine, and those disks still work. Can anyone shed any light on the subject? Ian Primus ian_primus(a)yahoo.com