Contact-tracing apps: "The performance art people will tie a phone to a dog and let it run around the park; the Russians will use the app to run service-denial attacks .... little Johnny will self-report symptoms to get the whole school sent home." https://www.lightbluetouchpaper.org/2020/04/12/contact-tracing-in-the-real-world/

"Bluetooth also goes through plasterboard ... The bluetooth app will flag up not just the others in the room but people in the next room too." https://www.lightbluetouchpaper.org/2020/04/12/contact-tracing-in-the-real-world/

"If the app’s voluntary, nobody has an incentive to use it, except tinkerers and people who religiously comply with whatever the government asks. If uptake remains at 10-15% as in Singapore, it won’t be much use and we’ll need to hire more contact tracers" https://www.lightbluetouchpaper.org/2020/04/12/contact-tracing-in-the-real-world/

"Apps that involve compulsion, such as ... quarantine geofencing, will face a more adversarial threat model; same true in spades for any electronic immunity certificate. There the incentive to cheat will be extreme & we might be better off with paper serology test certificates"

"rhetoric of terror puffed up security agencies at expense of public health, predisposing US and UK governments to disregard lesson of SARS in 2003 & MERS in 2015—unlike the governments of China, Singapore, Taiwan & South Korea ...we need is a radical redistribution of resources"

And on limitations of contact-tracing apps see below, too. https://twitter.com/jamescrabtree/status/1249638575651446785?s=20