Yes. Assuming the tax actually works as expected (it's probably too soon to tell now), the burden will be shifted onto other cities that are too stupid or dysfunctional to enact the same tax.

I don't see a problem here. The problem will correct itself eventually, with regular citydwellers all moving to cities smart enough to enact these laws, and abandoning cities like London that become completely unaffordable. Eventually the latter cities will collapse, and these wealthy foreigners' properties will be worthless, like all the $100 houses in Detroit.