At first, I was told it would be around $320 or so, with labor. I argued a bit, and they popped up with that statement that the repeaters were, "Working as designed."
I prepared to pay up. The guy showed, replaced them, and I didn't get charged. Checked the invoice again and they were replaced under warranty.
Some people here say they've been paying; a couple say it's been under warranty. Those that had one camera with glare and the other without seemed to get more traction on getting a warranty repair.
I gave my invoice number to three people upon request. One said that the SC in Washington State stated, invoice or no invoice, that that guy was paying. The other two haven't reported back.
So, at this point, it looks like it's all over the map and YMMV.
My opinion as an engineer: Nobody purposely designs a camera to have light leaks that cause glare. The appropriate phase here is, "Design defect." Some of the replacement lights have tape over the via holes where the light leaks in and over another spot on the camera printed board assembly which is transparent enough to let turn signal light in. Even newer ones have a different PBA which apparently blocks all the light.
One of the posters on this thread actually got a number of these cameras, cut them open to figure out what was happening, confirmed the design fault, and figured out a way (with accurate directions, even!) that, with a dremel tool and/or drill, to open up the body of the light (it's glued, permanently) so one can reach into two spot, paint the offending spots over to block the light bleed, seal the whole thing up with putty, and replace them. Cool if one is handy, but fraught in case one makes a mistake.
If it's a "design defect" there are many jurisdictions where it would not be covered under warranty.
Square Peg Meet Round Hole - Do Design Defects Breach a Warranty Against Defects in Material or Workmanship? - Fredrikson & Byron · Fredrikson & Byron, P.A.
For example you can look at GM, which had a lawsuit thrown out over this recently. They were able to argue cracking/warping/bending rims were a "design defect" and thus would not be covered under their warranty. Their warranty only covers materials and workmanship defects (which seems to be the same wording Tesla is using).
Lawsuit Over Corvette Cracked Rims Dismissed In California
Chevy Corvette Cracked Rims Lawsuit Dismissed
There is however a second provision that applies in California, regardless of what the warranty says, due to the Song-Beverly Act: "a plaintiff must allege a fundamental defect that renders the product unfit for its ordinary purpose." I'm guessing this is the one that most people will argue under.
However, as linked above, the argument against that is that the people asking for retrofits largely bought before the blind spot camera existed, so that is not something Tesla is responsible for. Basically Tesla didn't design the camera originally for this purpose, so the fact that there is glare from the holes at night that affects this functionality (I should note also the glare also exists on cameras without the holes, like mine with the revision C, so that is not the only problem either, the transparent glue also plays a part) isn't something that the warranty covers.
Up thread there is the argument over its effects on AP or FSD, but those are much harder to prove and Tesla can also point to the fact that complaints about this only came up over the blind spot camera, not over AP lane change functionality, as evidence its impact on AP/FSD is not significant, if any. The Corvette lawsuit also covers deceptive practices and fraud related to this, looking into the complaints that happened before the owner bought the vehicle. There were 11 cases prior, but most of them seemed to be from road damage; a bulk (30) of the complaints came after. That indicates even if there was really a defect, it suggested GM didn't necessarily know about it when selling the vehicle to the plaintiff.
The only case where someone may win easily is the case with one camera having the issue and one not. I imagine most judges/juries would even accept that as a materials/workmanship defect, given its an apparent difference occurring in a single car. And so far it seems Tesla has no problem covering things under warranty in that case.
As for Tesla covering a case (or a few) under warranty where it occurs in both cameras and that somehow setting a legal precedent, I wasn't able to find any reference to that being how things work. If there was a lawsuit related to this feature, that might set a legal precedent (presuming it wasn't just settled out of court), but I'm not seeing how an SC covering a certain case under warranty would suddenly mean Tesla would be legally obligated to cover all cases under warranty. But disclaimer that IANAL, the above is just what I found trying to find similar cases that covers the most legal arguments over warranties.