While it is better to err on the side of caution, there is a bit of overthinking here. Like Mikey said, send what has been agreed upon and, if some "hitchhikers" or "bodyguards" just happen to ride along, hey, nothing wrong with that!
Keep it simple, keep it within your budget. On the other hand, if you feel that someone is going out of their way to help you out, well, like at a restaurant with excellent service, tip accordingly.
Eventually you'll come up with your own comfortable levels and laugh when you look back at this post.