hi George
well my company requires us to get in by 2hrs from call out. they say that allows 30mins grace to get in uniform then 90mins to report for the flight.
i happen to live quite a distance from my home base and require the full amount of time to get in on time if called out for a last minute standby.
its never been an issue for me in almost 7years and i know of guys that live further than me that have never had an issue. if we were delaying flights constantly then i think some one would say something but until then it seems to work.
besides, most standby call outs are made asap so you tend to get called much earlier than the minimum 2hr before ETD, sometimes even the day before you will know. i can count on one hand how many times its been last minute and even then we're told to just do our best because it tends to be a bit of a mess at that point (10 crew all on last minute call outs coupled with tech delays leads to approx departure figures)
hope this helps but then again i work for a great company who do things in a traditional way.
cheers