Great. Hope they did plenty of expensive damage to the cars, which will really serve them right, and the fact that their stupidity is now on the internet for all to see just adds to the punishment, which is far worse than any fine.
I don't think they would work at level crossings though, since the main problems are at open crossings, where fitting them would probably cost more than fitting barriers, and at half barrier crossing, where fitting them to the exit side would block the exit to the crossing, which wouldn't be allowed, and would actually be an accident risk. Also, I doubt they would be substantial enough to deal with a heavy vehicle, or even a car travelling at high speed. You're also adding an extra accident risk where someone tries to outrun the bollards and they come up under the vehicle, causing it to stop on the crossing. The only real way to deal seriously reduce the risk of incidents on level crossings is to either close them or to convert them all to CCTV or locally monitored full barrier crossings with barriers substantial enough so that nothing is going to get through enough to foul the running lines.