It's gonna be redundant for you, But this is for the good of the game, making it more fair and having a healthier community around it. It's now 2020, and I'm gonna give some better solutions than the current one. It's gonna be a Quick read, I promise.

1st Solution: Currently there's 2 Lockdown queues: The classic one and Untiered. There's space for a Third that doesn't allow auto target.

2nd Solution: Revert back with few adjustments the possibility to Pay at the start of every match for Disabling auto target. Just don't take advantage of it and make it affordable. Could be 5-10ce or 500-750cr, don't go greedy.
You gonna have 2 windows choices: One for filling the prize, and the other dedicated to the Ban of auto target.

3rd Solution: Make the Lockdown Events Predictable. Give specific days in which those events gonna be guaranteed 100% to be on, so people that despite such Controversial feature knows Exactly When to play Lockdown.

4th Most reasonable and logical Solution: Just Ban It Permanently from Lockdown. So simple yet so Effective.
But I KNOW. I KNOW, you hate this one. This is why, You should consider one of the first 3 Solutions, while being the 1st and 2nd my personal favourite Sweets Spots.

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A Transparent reply from Any of the Grey Havens Staff regarding this topic gonna be Highly appreciated, just so we understand your exact intentions and reasons of why there's so much Persistence in keeping such broken feature in Lockdown. The way that Spiral Knights works, makes the fights fast paced, intense and requires mechanical skills, thing that Auto Target oversimplify and makes it a easy feature to Abuse. You should acknowledge that This is for the Integrity and Fair Play of the game. There's a reason if players have been complaining and fighting against it during these years, not just because they were bored or something. Waiting for a response.