By actually speaking to visitors the guys running the airfield, and ultimately responsible for the safe and continued operation of the airfield, know that they understand any local issues and procedures. Without speaking to them there will always be doubt about them knowing the facts.
Another example, at the gliding airfield I was once based at PPR is required. This was to ensure someone would be there to 'help' visitors but the primary reason is to ensure that visitors knew about how the gliding operations worked, no overhead joins, etc. You can attempt to write down on a website this information but it cannot beat actually explaining it in person, and making adjustments to the brief to cover certain short term events. Example, one day they may have some extra activity due to a visiting club, or there may be more cable launches due to no tug pilot, etc.