I'm an inveterate gardener of median strips -- the patches of dirt you find between a typical American sidewalk and the street. If you don't garden them they become breeding grounds for weeds, which I define as any promiscuously self-seeding plant that you don't want in your yard. If you do dig over these beds and plant them up, you get a whole extra piece of yard, with different sun exposures, allowing you to extend your planting and, you hope, delighting your neighbors and furthering the beauty of your street.
Of course these strips don't belong to you. They're owned by your local city, which puts the status of the plants sitting in those strips question. Whose are they?
I was reminded of this today walking past my neighbor's spectacular hedge of Japanese flowering quince (Chaenomeles). It's now in full flower and a joy for anyone going down our street to behold.
But every year, about this time, I see at least one person helping him or herself to a personal bouquet of quince blooms -- someone whom, I know (because I know the owners of the house that borders the strip), typically hasn't asked permission to cut the flowers. The result is fewer blooms for the rest of us to enjoy and -- usually -- a poorly pruned quince. But if the land belongs to the city, was the clipper really doing anything wrong?
Maybe the right thing to do is to call the city and ask their permission -- I'm not sure they'd care either way, really. But I think one should ask the owners too, mostly out of respect for the people who have (demonstrably) tended a plant of enough beauty that people would like a part of it for themselves.
I've had the same thing happen. My rule is that children under five get excused, but that anyone older is asked, politely but firmly, to refrain. Another local friend has a persimmon tree in her median, a fuyu, from which the fruits need to be cut and not pulled -- otherwise you really trash next year's fruiting branches. She's always very generous with her crop and usually posts a sign begging people not to pick but to knock instead and ask for fruit when she's clipped it off, which she'll then share. Last year, though, pickers ripped off nearly all of her fruit and so this year she's had nothing to share with anyone. We all lost out.