Brake fluid on brake pads ruined?

Yes and in fact even more so as the front brakes do 75% of the work.

That and pads are so cheap, even if you're 99% sure they're ok, change them anyway - they're quite important...

I once had a flexi hose burst at the front of one of my old cars. I went to one of the fast fit places through desperation. Bloke says, "You're going to need new pads and discs, as the brake fluid has contaminated them." I asked him how the fluid could contaminate a solid steel disc, answer to which was "Er, I'll give the discs a clean.." Fecking chancers!

Dead easy, if you brake on it before you clean it. I don't know the chemistry, but the stuff burns on as a lacquer and won't shift.

_If_ you've got a runway handy and a clean set of pads, then a dose of braking will take it off in time -- but don't do this on a road, you've got asymmetric front brakes and you very likely will spin it.

Silicone Dot 5 fluid is a bastard to remove from disks. I don't think this is possible by braking action.

Welcome to wire wool.

Never tried DOT5 but had 5.1 (non-silicone) on my pads a few times through sheer laziness during working on the car - as you say, providing you get it off the discs and pads fairly quick you're usually ok just being cautious for a few miles - though I normally take a flat piece of wood and a fairly coarse sandpaper to the pad surface to remove the residue.