when i was on call i would not turn my phone on until i was awake and ready. a couple times being woke up after 4 hours taught that. also we could pass up work by seniority. sometimes you have no choice if no one else is available.
when i was on the bottom and did not work for a couple days, sometimes i would work for someone else. they tried to discipline me for this could not. we have a rule that you have to be layed off for 4 straight days before you can work back in the building.
i told them that i have bills to pay and since they were not paying me "Standby" time they would have to pound sand or hire more feeder drivers ( which they eventually did) My BA backed me on that. He even told UPS that they would have to start paying standby time if they tried firing someone for not being available.
anyway, being on call is basically a bitch until you move up enough to win a weekly job or a bid run.
another example of the company thinking they OWN you even when they are not paying you.