My store is in the process of unionizing (filed and waiting to vote), and the answer is pretty much nothing should happen to SM's unless Corporate is feeling dickish and sneakily punishes you for "allowing" your store to unionize.

Although if you're an SM on bad terms with your store then they may decide to demand your removal but so I haven't seen that happen yet.

Edit: I'm a barista, not an SM, btw

I know a couple of the Buffalo region stores, as well as the first Mesa location that petitioned, saw very sudden changes in management. I believe Mesa's manager quit, but there have been reports of SMs being suddenly terminated or relocated. I'm not sure if that's because the SM was on bad terms with the store or what, but there are reports of it happening.

But no, forming a union doesn't immediately make the SM role useless, the store still has to be run. Corporate shouldn't really do anything to SMs, I imagine they're telling you guys that in an attempt to turn you against the union. With the number of unionising stores hitting 150 this week, I feel like they won't be able to keep cycling management in stores. There has to be a point where it's no longer feasible...

Note that I'm not an SM, and I haven't been a barista since 2019. Just an angry ex-barista that's been fervently following the efforts since it started last year.

I heard of one confirmed case where an SM was demoted to shift. I've heard a few other unconfirmed cases of demotion to ASM, Shift, or termination entirely.

As a store manager, if my store starts talking about unionization I will immediately stop down.