Privacy laws: Can a stranger video record you in public without consent?

It depends on where you live, like most things that are a law.

For the UK and USA it is true that you can be publicly recorded with no real recourse unless you can tie it to something like harassment, sexual or otherwise.

In Sweden it is illegal to record public places with static cameras, and I highly suspect that the Swedish police/court system would side with you if you decided to pursue a punitive measure of some kind to someone who is fragrantly denying a request not to be recorded.

In the US and much of Canada you can generally record someone in public, if there is no expectation of privacy -- e.g. someone on the street can see into your yard.

Some of the provinces in Canada have more nuanced rules, and I believe Quebec is the strictest in that you can't have cameras pointed at someone's windows.

In the USA, anything seen from a public space, including the air, the street/sidewalk, even aimed at your yard, is legal. In most cases you can even film on someones private property if there is easement. There are exceptions, but rarely. Privacy was assumed, but never protected here.