I don't think it's just young mums! Plenty of older mums pushing away.
Or people that just stop in doorways/pavements. That's what gets me really annoys me!
I agree to an extent.
I will usually hold my line and then just stop infront of them. When they suddenly look up startled give them a bit of a 'look where you're going mate' and they will usually apologise and walk around you.
We are all guilt of social faux pas so I wouldn't want to be too...