Individuals in the Reserves are a very different story. For example, if a Reservist fails to show up for monthly drills, they are likely to get a “bad discharge” that would affect any benefits they may otherwise be entitled to (however limited those usually are).
If a Reservists fails to report after an upcoming deployment that has been announced by their commend, even if the announcement was done so informally and without actual orders, they may eventually be charged with AWOL/UA or even courts-martialed for Missing Movement. Other outcomes, such as non-judicial punishment or a discharge in lieu of court-martial are other possibilities in these situations.
As a member of the Reserves, the military does have the ability to take action against you for refusing to drill, deploy, etc. under the UCMJ.
Prior to 2001, Reserve drill “no shows” were often simply dropped, eventually—many received an honorable discharge because it was the easiest administrative route for the local command. That is not currently the situation.