I appreciate that pushchairs take up a lot of space, but hey, people with children need to move too. Apart from the fact that we normally have to wait for several buses to pass before there's space for us to get on, it doesn't add to the general atmosphere when some of the other occupants of the bus start moaning about your poussette.
It's not just the weekends, either. Same thing happened Friday at 11am, and pretty much every other time I've taken the bus in Paris with my kids. Given that during the day time the people who need to travel are non-workers, that means there's a lot of disgruntled parents and elderly people. So can we try to co-exist peacefully? Ta.
p.s. Pere Lachaise was a good idea for a spring day - plenty of roads that you can push the poussette on, and little ones can wander around collecting twigs without fear of crowds, cars or joggers.