G.B.
I usually do play dates with someone I don't know in a neutral place like McDonalds or the park if the weather is nice. You don't know if that person is a potty mouth, or smokes like a chimney, or is one of the nicest new friends you'll ever meet. If you are someplace neutral you can always make excuses and leave. If they are enjoying themselves and you are comfortable there is food and drinks for you to enjoy also.
I would not let my kids go to someone else's home without me until I was VERY familiar with their parenting style and was comfortable with how their home was set up as far as kid friendly and not dangerous, like bad dogs in the back yard....just pays to know exactly what is going to happen. I always stayed with.