Trust: When to Let Go

One thing I have considered since moving to a much smaller town is whether I will find it easier or harder to en-trust my kids to someone else's care. I am basically a permanent stay at home parent (until somehow that changes), and we have rarely left our kids with anyone, aside from our own parents. Regardless how close or how friendly someone may be, we have always felt more comfortable having each of our kids with us, and have learned to do pretty much anything with the plan that they will come along. Grocery shopping with 3 kids: check. Coffee date with 3 kids: check. Night away with 3 kids: check. Some may laugh, but I happily identify with the "attachment parenting" label, and have no plan to change that. This is the time in my life where I prepare to either send my oldest to public school or keep him home with me. In one year, depending on what is officially decided he may be off to school with many other kids and not at home where he has always been. I don't have much against public school, that's how I was educated growing up. Since growing up though, and becoming a mom, there are certain things which make me want to educate my kids otherwise, which I will not get into tonight. Back to the trust thing. People here are really friendly, which I totally appreciate and enjoy coming from a big city. There is an openness here that you don't get in a metropolis where people wonder why they haven't met you and want to know your name. They're excited we're here and want to know us. I'm not sure what it is that makes me want to doubt that I can trust them. Not everybody, but some and while I know most people are genuinely friendly and wouldn't harm a fly, I feel fiercly protective of my kids from people that I do not know. Would I want my kids alone with them? Should I let my kids get close to them? What boundaries are appropriate? I don't know exactly what has caused me to build my guard higher here, but I suppose more than anything it's my responsibility to protect my kids and screen anyone who thinks or assumes they have a right to any time with them. That's my prerogative, no? I'm sure there will come a time when my kids get older where they might actually be the ones to force me to let go a little, and allow them to use their own judgment when it comes to relationships, but for now I have 3 young ones who require me to be the protective eagle mother and use my distictive mother instinct for their benefit. Just something that's taken up some space in my head the last little while. How do you educate your kids on relationships, and boundaries? How do you deal with trust when it comes to protecting your kids? I would love to know your thoughts.