I intentionally crashed my e-bike into the side of a car that pulled up without looking onto the bike lane. Then I showered him with expletives. Also slapped the hood of a few cars on Xuefu lu that were in the bike lane and trying to get past the little bus stop. It may not help but it feels so sweet.

Some day I want to be brave enough like that foreigner in Beijing who just stopped his bike in front of a car in the bike lane and forced the driver to reverse out.

so much for your Zen, Colin :)

车让摩托让单车让行人 - then all will be good

Slamming your hand on the hood is an effective method to deal with pricks in expensive cars. It makes them so furious but there's no way they can catch you as you slip away like an eel among the shoal of two-wheelers.

10 RMB or about 30000 VND will also get you a ride on a scooter.

No there isn't. You'd have to cross the border by yourself and then you can get a bus to Sapa. There are many options from official buses to mianbaoche equivalents. The ride is about 30 km up a hill so I'm guessing anything between 30 min and 1 hr to get to Sa Pa.