Absolutely! I am not spray-resistant but as a backyard hobby grower I would like to be as organic as reasonably possible. I really like the idea of allowing the fruit to remain attached without affecting the stem or risking fruit fall by having entire sections covered. For heavy setting plums like your Shiro I think you really nailed it with this flat-bag idea Mamuang. Plus it allows for air movement.
I worked this whole weekend (owww, feet hurt) but I was thinking quite a lot about learning that Jellyman from GW had heartbreaking losses due to BMSB biting through conventional bags. I was contemplating the weakness of bagging: the flat lie of the plastic over the fruit surface, which allows a bite through the plastic. That is why I used pipe cleaners to make a ‘dome’ for my peach bags: no direct contact between fruit surface and bag. But it was quite hand-crafty and possibly too labor intensive and impractical for an average tree-sized crop. So… bubble wrap came to mind, as the depth of the bubble compartments must surely exceed the reach of even BMSB mouthparts even as fruit grows wider and the surface angle of the fruit touches the inner surface of the bag .
They make these bags, and while a bit expensive to buy they would possibly be re-usable:
Some cuts for fluid flow would still need to be made in these bags. Am now also contemplating bubble-wrap sleeves, inspired by your flat bread bag sleeving.