The higher the barrier to sharing things, the fewer things will be shared. "WE won't lose anything but low quality dross that wasn't worth anything" is the usual counter argument, but that's an oversimplification at best. The long tail of "low attention" things provide room for the sparking and evolution of new ideas for which there is no room in the "high attention" center.
So, no: there shouldn't be any block to sharing anything someone feels moved to donate to the world.