When an attendee first arrives at an event the first interaction that they have with a representative of the event is when they approach the event site and encounter event safety or security staff.
How the next few minutes go can frame that attendees whole event experience.
To optimise the attendees experience there first impression needs to be a good one. This then sets the tone for there entire time at an event. It also means that if you need to speak with them later or challenge there behavior that they are likely to be more receptive.
So, it is all about the little things. Greet them. Talk with them. Understand that this could be there first visit to the site so perhaps mention where facilities that may be of interest to them are located.
Ask yourself a simple question. If I was this person how would I like to be treated and what would wow me. Once you have the answer to this question then you also have the guide on how to treat them.
If you don't create a good first impression then this can cause problems.
The attendee can become aggressive or enter the event in a bad mood or with the impression that event staff are "jobsworths". This in turn can effect every other interaction with staff during there presence at the event.
As an example many years ago I was working a football game where the rules were that children could sit on sponsor boards so long as they were being supported by an adult behind them. During the first half a member of the event staff had spoken with a supporter who had two children and was only supporting them both partially. There interaction did not go well.
When I was patrolling through in the second half I found the same person in the same situation. When the attendee saw me he responded very aggressively. The behavior was such that I could quite legitimately have him ejected or arrested.
Instead, I moved alongside him, pointed to a group of event safety staff in the corner and told him that my boss thinks that I'm talking with you the fact that your children can't both be on the boards whilst you are standing here alone. Not to worry though because I have a sneaky suspicion that our conversation is going to finish around the time when you are no longer alone.
Thankfully this managed to defuse the situation but it was one that could have been avoided had the first impression been better.