If you’re pushed in it’ll be no different to being pushed into one of those kid’s pools. Are all these people being pushed in and drowning less than 3 feet tall so they can’t touch the bottom?
If someone said “watch out, there’s a canal pusher about”, I’d say “yeah, my brand new Levis would totally drown in that dirty, elongated kiddy pool. The canal pusher is a murderer alright, murdering perfectly good clothes.”
I don’t know anything about any pushers, but as someone who’s almost 2m and had fallen into a canal - I can tell right now it’s not 3 feet. My 2 feet could only reach the soft muddy bottom at the side.