There's a lot of sides to this... those that don't want any kind impingement to their privileges whatsoever... those that wouldn't mind as long as it was fair... and those without privileges that want to see something other than apparent inactivity when a contributor upload bypasses the queue only for it be later flagged and deleted.
Maintaining the status quo will only serve to discourage non-contributors as this thread has shown. Imposing any kind of immediate restriction on contributors without due cause will only discourage those contributors who worked long and hard to earn that privilege, also as this thread has shown.
Maybe a compromise is in order...?
This is just a suggestion, but maybe a graduated system of restrictions could be used...
Level 0 would be as it currently stands with the unlimited uploads permission. However, if a certain number of queue-bypass uploads are flagged and then subsequently deleted within a certain time period, then that user would be moved to Level 1 restrictions.
Level 1 would send a certain random percentage of queue-bypass uploads back to the moderation queue. If they prove themselves again by having under a certain amount of deleted uploads, then they'll be moved back to Level 0. If however their deleted uploads exceeds a certain amount, then they would be moved to Level 2, and so on and so forth.
The above gives a general idea for the system, although the specific details would need to be fleshed out if it were to be accepted. Note that I did not include user uploads specifically sent to the queue as counting negatively towards the user. This shows judgement and an honest asking for a second opinion, neither of which should be punished, else why would a contributor choose to send a picture to the queue if it'll affect them negatively either way if it gets deleted.
The above is just a suggested compromise between both sides. If anyone has a better idea, please share it with the community.