At least on the 7315 side of the house we've heard rumblings about this coming down the pipe for a bit. It really doesn't help that every company grade officer in one squadron submitted IST packages. We are looking at losing an entire year group. But hey, let's not fix things, let's just make them not able to leave.
That's definitely a thing, but you' have to get a conditional release from the IRR- which used to be given out like candy. It's not working out for a couple of dudes who were just told, "Well, you can accept activation orders for a unit in 4th MAW or you can stay in the USMC IRR..." No thanks...
This is the shit n00b debbils (and to a similar extent) baby squids need to be paying attention to, not how to do pull ups or write motarded statements or whatever the fuck else they do before you show up at flight school.
You are going to give an organization some of the best years of your life and they are going to thank you by trying to rawdog you with a sandpaper dildo at the halfway point and actively take away options for your future.
No one is going to tell you this shit can or is happening before you sign away a decade of your life. Think about what that says about the character of those organizations and their leaders.