Less unfair than not getting a vote at all because your post expires. I don't see any other solution than having an adaptive voting threshold. But perhaps there is a more elegant implementation.
Also it's not necessarily a bad thing to encourage posts when the usage is low, to help create a consistent reviewer load.
Well.. that is true. The problem is, commits have to be 14 days old max, so sometimes you cannot wait for a less full queue. But I am sure they will come up with something good if needed :)