Speaking from 10 years of commercial driving (school bus, don't you know), receiving a DUI while operating a commercial vehicle is an automatic revocation of your license in most states (and that includes your Class C [normal automobile] license).  The producer would be required to replace an offending driver.

DUI by an actor in his own vehicle--the only way it should impact the show (unless he is touring with a religious group who has standards against drinking or overindulging) would be if he were incarcerated (jail time) during the run.

In professional theater, half-hour call before curtain is fairly standard.  Unless their makeup, costume or warm-up procedures are very extensive or elaborate it would be unusual to require professional actors to arrive earlier than that.

That being said, there is nothing preventing actors from arriving at the theater BEFORE call (unless the doors are locked and the SM cannot let them in).  The SM is usually prepping the show at least an hour before showtime.  Usually it is the female actors who need to arrive early to spend time on their hair and don't want to rush.

If an actor arrives late, it is usually the SM who reprimands them.  The SM's wristwatch is always right.  Fines are not uncommon (anywhere from $5 on up to $50 or more) which can take quite a bite out of performer's salary on the road. 

Unless the SM was "trying to teach them a lesson" there would be no reason to prevent a late-arriving actor to sit out a performance in favor of their understudy.  And, depending on how much clout the actor might wield with the Producer or Patrons, the SM might be considered to be overstepping his authority to exclude the tardy actor.  In that case, it would the SM who was reprimanded for "not keeping closer accountability of their cast."

The SM might say, "The curtain goes up in five minutes; will you be ready?"  If not, it is up to the SM to hold the curtain for a reasonable time until the actor is placed.  I've seen situations where the show has already started, the understudy is in place, but the character who's missing has not made their first entrance yet.  The late-arriving actor makes it to the theater before his first cue, slaps on his costume and make-up and breezes onto the stage.  

If the show has already started, and said actor has already missed his first entrance, then it is most likely the understudy would complete that performance and the tardy actor would be penalized by fine or dock in salary.

This is where the messy problems of contracts come into play.  Most contracts would state that the actor on tour is obligated to a minimum number of performances per week.  If the actor fails to achieve that minimum, the producer can arbitrate this matter as he sees fit.  Fines, cuts in salary or even dismissal are all options.

And Joan 54 is right.  Peer pressure from the rest of the cast, or losing face in the presence of one's colleagues often carries much more weight than any monetary or legal consequences.