I will try to keep this post short and I apologise if I get long winded!!
I own rental property in my hometown and out of state. The property I have here had a sewer back up. 1 home was built in 1907 so the sewer pipes are aged. I had to get 2 different plumbers to inspect and snake the lines. I asked the last company to send a camera down and I also had 2 City Public Works staff members to witness/determine and verify that it was a City owned tree intrusion into the sewer line and to pinpoint exactly where the intrusion was. The intrusion (roots) was 2 feet away from the curb (my property side) so that put it in the 'strip' that we are talking about. I was fully prepared that the City would pay for the repairs. Stupid me!!!!
Bottom line, I am responsible for all costs. The plumbers costs/the cost of repairs to the sewer line, replacement and labor etc; which will all amount to several thousand dollars. If the problem was in the street, it would be the City that would pay for the repairs.
I was annoyed (putting it very mildly) that it was a City owned tree that was the problem.....I cannot cut it down/stump grind or even trim it back etc; It is totally up to the City to determine if they want to remove the tree and also this incident doesn't mean it will be removed.
I cannot speak for other City ordinances but the curb strips here are owned by the City but the property owner is fully responsible for all damages that occur in the strip. Slips and falls etc;.
The reason I'm sharing this is.....IF....I did not have a passion for metal detecting, I'd maybe get concerned seeing some guy digging around property that I am responsible for and if he or she gets injured, they can sue me.
It's a personal choice to detect those curb strips but I personally err on the side of NOT detecting that piece of property. It's a fine line of getting some property owners really pi@#*@$-ed off

. There are many other places for me to detect away from potentially upsetting people. Besides, it would not be enjoyable for me to be looking over my shoulder at people behind the drapes perhaps calling the cops on me even though I have the 'right' to detect. Thanks for bringing this topic up!!!