I think most guilds have been there. Because of work or travel (or apathy) we usually get 40-43 participants. Sometimes we get matched against a guild with great participation getting 50 - and it feels to them like we are sandbagging. I know there are guilds that intentionally run 30 (and force sit 20) and that really doesn’t feel like the spirit of the game- but even with that aside the matchmaking feels like it delivers a lopsided match two thirds of the time (at least) and maybe a competitive battle in only one third of the TWs.
I think the body of your email is finding fault with the algorithm and the rules as opposed to sandbagging. Is it better than the previous version of matchmaking? I think so?
I am worried that Relic delta will make sandbagging more popular as those high relic defensive teams will be harder for smaller guilds to displace.