The "official" phrase is called "standing time", and it is the amount of money most unionized labor charges per hour while being customer mandated to be on-site but not performing their exact work function.
Following unionized labor's ideology, the billing process employed is that if the client demands of event timing are out of line with my normal timing, they pay for the difference, at a rate of 50% of my normal overtime fee charges.
In other words, if a normal wedding begins with intros at 7:00pm with the business policy being to arrive on-site one hour ahead of the contracted start-time, say a particular client wants the setup be completed by 4:00pm. That means arrivial now needs to be 3:00pm. That's three hours of "standing time". The client would be 1) advised of the math; 2) advised of the per hour "standing time" fee; 3) then consulted regarding possible work-around.
If doing a ceremony, not the cocktail hour, then the reception, a "standing time" fee is included in the quoted price but may not be specifically mentioned as such unless it would entice the client's mindset to rethink their cocktail hour entertainment toward my services for an extremely reasonable additional charge.
It is also important to mention that we're not talking chump change fees. If one's overtime rate is like $50/hour, none of this matters. If that's all one values their free (or working) time, what's fifty bucks. Tossing it in as a no charge will have the same mental read on the client, e.g. chump change.
Being one of those arrogant, pushy, nickel & diming, want to be paid for everything I do in business kinda guy, my "standing time fee" is one half my working overtime rate ($300/hour) which thus is $150/hour, the rate proudly quoted to stand around doing nothing because the client made it a part of their demands on my time.
Conversely, if I wish to arrive at a venue 5 hours early for my own personal convenience? No charge. Do a ceremony, go shopping during cocktail hour, then come back and do the reception? No charge.
Every inconvenience has its price. Extra equipment of any kind, extra travel of any kind, extra time of any kind...all billable. I hate wasting time, especially if it's not my choice.