We've talked to DS about stranger danger and he's been good about that so far. He's gotten lots of bumps, bruises, and scraped knees from playing too rough or going too fast, climbing too high. DH and I are fully aware of the dangers of his endeavors (I'm an acute care peds nurse and see the worst-case scenarios every day); hence why people think we are helicopter parents for always watching him like a hawk. We only let 3 other people watch him because we trust that they will not let him go unsupervised and will jump in when (not if) they need to. He's only 22 months, so I think a child leash will be a HUGE help. Normally, I strap him in the Ergo for trips to keep him out of trouble, but DH thinks that the front seat of the carts are good enough (lesson learned, lol).
Talking to him about hazards of streets, cars, large equipment, fire, heights, animals, etc. have normally been understood and he's proven that he'll stop and look for assistance for the most part, but that independent streak of his and unabashed curiosity will get the best of me, I swear. He never cries over pain, falls, trips, near-misses, etc. so I'm not sure how to explain morbidity and mortality to him.

Puffin and Indigo, I'm glad I'm not the only one who needs extra locks and door alarms, lol. Just last week, I thought I'd outsmart him and wake up super early to catch him before he could go out the front door. I walked downstairs at a quarter to six to catch him in the act of making me coffee. He had managed to get his step stool, grab a coffee mug, fill it with water, plug in the Keurig, fill the water compartment, turn the machine on, put in the K-up and was closing the lid and pushing the brew button. There isn't a strong enough coffee to keep up with this kid, but boy was he proud when he saw me coming! I was super grateful as he beat me to it! Such a little man and yet so considerate.