Not to mention you'll break up a paceline and piss everyone off if you do some hard backpedaling.

Really light backpedaling isn't an issue though. I guess at that point it's not really backpedaling, just the absense of forward pedaling and just letting the pedals move your legs for you.

At one point in a race last season I was near skip stopping from backpedaling so hard because I sprinted for a finish and lapped someone right at the line and he started turning where I was headed without looking, leaving me little room to work with...