Well, regardless of whether it does it now, it remains a viable option for mitigating the exploits enabled by this. 
Why even have a warchest then?
I thought the goal of a war-chest was to transfer costs of supporting units to the sponsor from the knights.
If repairs cost 40 gold without a war chest, why would I want to pay a total of 60 gold, just so that my knights only have to pay 20 gold?
I think IF such a feature was in place, I'd definitely want to know about it because I'd stop using war chests immediately. They're essentially counter productive.
