OP- it’s never a bad thing to review basic urban safety when alone at night with your son.
Wearing obviously expensive items-- backpack, watch, trendy sneakers- not a good idea. Having headphones/earbuds in- terrible idea.
Making a quick stop to a cash machine- terrible idea.
Walking home while under the influence so your reflexes/reaction times are off- terrible idea.
Always have someone know when you are leaving point A and expect to arrive at point B.
When in doubt, it’s worth the extra $ for a taxi/uber.
You are not talking about particularly dangerous places… but if your son doesn’t have a lot of city experience, it’s worth a discussion.