Anyone know what these things are? They are recently stuck to nearly every sidewalk hatch on Folsom. Obviously they're tamper-evident seals, but my spidey sense tells me there's some kind of wireless electronics in them.
Previously, previously, previously, previously, previously, previously, previously.

i mean… there’s an easy way to find out if you have some implements of destruction….
And if I was a dick.
i feel like that depends a lot on the context around the town and their motivations to stick them everywhere.
"Don't destroy shit that isn't yours without a good reason" is a pretty good principle that I wish more people used.
yeah… can’t argue with that. :)
Maybe…unless that shit is locking down public resources.
How is this sticker denying you anything? Where did the bad sticker hurt you?
I’m just saying in the bigger picture. And spelunking!
Wise words from a publican that has spent many hours, and dollars, fixing shit that the heathen have found entertainment in tagging/shattering/flushing-things-down/fucking-on-top-of.
They're probably these - https://tydenbrooks.co.uk/shop/rubber-drain-cover-seals/ - those curves are perforations, making it hard to remove without tearing the entire seal.
I believe they are leftover from APEC. Secret Service put them out.
Better than welding them shut, which I think used to be standard practice when the rich, powerful, and cruel came to a city.
Probably the metal ones still get welded.
Looks like it. I don't understand why they have serial numbers if they aren't alive, though.
like any security seal: note the number when you place it, and when you come back to check, you can compare the number, to make sure the old one wasn't removed and a new seal put into its place.
Interesting. It would be really surprising if it was someone’s job to actually keep track of the S/N’s, but what do I know?
One semi-serious question. The product description states:
“Rubber Drain Cover Seals application guidance:
[…]”
Are the words “free of water” somehow more accurate than just saying “dry”? Or is this a British thing? OR… maybe someone is intentionally using obfuscatory language because they know how much their customers will appreciate it. (E.g. “officer-involved” removal of manhole cover”?)
If I had to guess, it's to stop people from deciding something is "dry enough" then complaining when the glue fails. "Free of water" is less ambiguous for the stupid and lazy.
I've been to places where they put asset tags on trees!
Utility poles have had serial numbers for years, for maintenance tracking. It's a lot easier/quicker to serialize manhole covers with stickers/seals than it is to retrofit the hardware.
Looks like https://www.jwproducts.co.uk/security-seals/manhole-seals/. It appears to just be a very expensive sticker.
Almost $20 a pop: https://web.archive.org/web/20230512080908/https://www.jwproducts.co.uk/drain-cover-seals/
+1 for APEC, saw them around Moscone then
The first time I encountered these things was October 2010 in Manchester. Labour had just held their conference and security was probably tight. I came to the same conclusions as you about their purpose and capabilities. Thanks to this post I now know I was wrong about their embedded RFID.
(Yes, there were obligatory visits to various Factory and Turing sites as well)

Is anyone else's OCD also triggered by the fact that the sticker is applied backwards? The curved side is supposed to be towards the outside!
No... Not until now, thanks.
Security Theatre. ("In this house we have the candour to spell it 'theatre'.")
K3n.