Unless, of course, your fork has the tiniest bit of incorrect spread between the legs, as every fork on every bike I've owned has had - then you still end up adjusting the skewer, even if you've filed off the tabs.

It does alarm me, though, that you consider adjusting a QR skewer such a big deal that you would recommend that people take a file to their bikes rather than risk having to do such major maintenance. I find skewers quick and easy to adjust, whether or not the bike in question has secondary retention tabs or not. I'm sure there's a 12-step program or something for skewerophobia.

Seriously, though, I would not suggest that anybody file them off without knowing EXACTLY what they're doing - not only do they serve more purpose than protecting fork manufacturers from liability (as mentioned in some of the above posts), but it's also an easy way to damage your fork beyond repair. Don't laugh - I've seen it more than once.