Admittedly, bike lighting is a solved problem by now, one shouldn't bike where you cannot see. There is always the risk of an obstacle you wouldn't expect, could be even an injured person blocking the way.

But of course, this doesn't justify any of those ridiculus and dangerous artificial blocks. Just clearly marking the bike paths with color should be good enough. If an car ever is caught there, well, rip apart the drivers license. Or just leave it to the bicyclists :p I have seen too many of those blockages myself, they are dangerous and often enough I cannot pass them with my bicycle.