Aside from safety reasons (on which I can't comment) there is no reason not to let bikes go faster in between the lines -- car drivers aren't losing anything. Maybe there are some hurt feelings because it feels unfair and perception that they should stand in line like everybody else, but that is unjustified as they don't slow down your kind of traffic (well, maybe marginally). So double standard here is perfectly justified.
(disclaimer: I don't drive bikes and we don't have too many of them on the roads most of the year)
well... "no reason not to" is not quite the same as "perfectly justified" but I kind of see your point. By that same logic though, there really isn't any reason not to let other vehicles lane split if it can be done safely.
(disclaimer: I don't drive bikes and we don't have too many of them on the roads most of the year)