Brisbane cyclists are seeing an increase in the (ab) use of thumbtracks. With this information going on national news, the tactics could easily spread to other cities.
Reading this took me back to my childhood (7-11ish) when my friends & I went to war with the local council greenkeepers. The local park was our home away from home (and we were always away from home, with bikes). One year they decided to spread thumbtacks throughout the park, and we spent countless days using magnets to pick up every single one of them (the parkways were all rough gravel so the thumbtacks would sit between that, quite invisible). As this cycle repeated itself a few times we ended up turning things around and we spread our whole pickings in front of the greenkeepers' depot. We ended stopping the abuse. The greenkeepers' foreman was the nastiest, he also chased us with a rake off a soccer field several times, kept harassing us at the fishing pond in the park, which ended with him being shoved in the pond, and broke a kid's glasses once as he attacked him.
Childhood... when you're in it you can't wait to grow up, when you're grown up you wish it had never ended :-)