Brides and grooms are ultimately responsible for the behavior of their guests at their wedding activities. When they rent a location for a wedding reception, for example, they're accepting responsibility for returning everything they are renting and using to the venue in the same condition it was in before their main event occurred.
The first time I sent a bride and groom a contract from a hotel wedding venue, they were shocked by the amount of responsibility they were required to assume for their event and their guests. Most places make brides and grooms assume liability for their vendors, and require the vendors to have a certain amount of their own insurance to work on the property.
At a private villa, the lease assigns responsibility for everything to the person signing it, meaning you are ultimately responsible for everything and everyone who comes on the property for the purposes of your wedding. Some properties charge an "event fee" that helps to offset their additional costs incurred by events (additional wear and tear, trash removal, etc.), and other private homes and venues will require you to pay an increased security deposit "just in case."
In case of what, you might be wondering. Allow me to fill in the blanks for those of you fortunate enough to have never seen a wedding group get out of control, or an accident occur at a party. Hotels and private venues have to protect their liability and their assets (materials and equipment that can be damaged) from potentially out-of-control guests.
Just in case a drunk guest dives into a shallow swimming pool and injures himself.
Just in case guests get out of control and dance on tables and chairs, breaking or damaging them in the best-case scenario—breaking and damaging themselves in the worst-case scenario.
Just in case the photographer leaves all his gear someplace where it can be tripped over and somebody takes a spill.
Just in case the DJ or band doesn't tape down their wires well enough and somebody trips, taking out the wedding cake and everything around it.
Are those enough examples to make my point? I think so.
Brides and grooms: Expect to be given a liability waiver and damage agreement from most wedding venues you consider, but don't let it freak you out. Many wedding planners have similar agreements with their clients. You shouldn't be afraid to take responsibility for the behavior of your wedding guests unless you know that your friends and family are badly behaved, likely to destroy property or cause damage. If that's the case, you need to take a step back and reconsider whether those people actually belong on your invitation list.
You thought renting everything was expensive—I assure you that having to buy it because you broke it costs far more. Wait until you see the bill for replacement items after everything is said and done. It's never inexpensive to pay for things your guests intentionally damaged. And that's why the bride and groom are held responsible.