I have not seen that before, it is an interesting solution though.

The bracing seems excessive to me, but I do agree with the statement "This adds strength to the front of the ABS tub."

There is a bit of flex where the idlers meet the lower hull due to the track ~running~ tension through tall grass or sand.

It may be useful for that purpose. I simply reinforced that particular area with some additional styrene thick stock.

I have never had a track come off, although some track stretching can be expected over time.