Braking

[darrsi]

I use both. Mostly front and a bit of rear for normal stopping and mostly rear for low speed stopping. I was taught 70-30 front to rear. The way I see it even if the front brakes have 90% of the bike's stopping power if you don't use the rear you're down 10% braking power so use them. For carrying a pillion too if you only use the front I've found a lot of headbutting goes on whereas using both keeps the bike more stable and stops the headbutting

Same as in traffic, if you only use the front it plunges the front end, it's overkill.

As for rear locking up, that happens when the clutch is pulled in, mainly in an emergency where you can't help grabbing everything in a panic situation.
I've taught myself not to pull the clutch in, but it's a natural reaction to clench everything available when faced with danger!