Definitely hiring security gaurd is a good support system to take care of your safety when you are focusing on the event. Give clear instructions with do's and dont's,set your expectations clear and protocols to be followed in case of any issues in the event. When security guards are around, you can focus on with your guests and event peacefully, without thinking about the safety. You can depute security officers from reputed security services, so that you can actually make your security guard accountable and have a control over the guard.