<p>During the year many professors understand if you need to register during class if that is where your time slot falls. Some even give everyone a 5 minute break. Besides for freshmen seminars, there is a lot of movement between classes once everyone gets to campus. If there is a particular class you want, just check banner every couple of days and chances are you can get it. Besides for a few extremely popular classes and seminars, I’ve rarely heard of someone not getting into the classes they wanted.</p>
<p>And yes, they check their emails. Some may be on vacation or teaching summer courses elsewhere, but I would guess that the vast majority are doing research - which usually necessitates the checking of email every once in a while.</p>