If you going to go ahead with a faction lock, it should only apply when queuing into a pop-locked faction.
That is, you may only queue into a pop-locked faction if you have set that faction as Home for the campaign. Otherwise, you can queue into any campaign and you are automatically registered on the leaderboard and for campaign rewards.
This would alleviate the impact on people who play outside of primetime while maintaining the efficacy of the faction lock for those who perceive there is some kind of unfairness to it.
To be clear, I don't want fation locks at all. But if they are going to happen over our objections, please consider an implementation that doesn't punish people who can only play in the wee hours of the American night or during the mornings.