In my CRJ class there was a 16-hour break between Indoc and Systems Day 1.

CASS takes about 2–3 weeks to be activated, if I recall correctly. Flight benefits, about 10 days. I nonrev'd home on United my first weekend of Indoc, only to discover after I returned to class that somehow a few of us had gotten away with it...our flight benefits had been mistakenly activated too early. United never bothered anyone about it, though.