You might note that I, in fact, suggested the pay-to-park scheme, and the subway ticket scheme. It's actually quite simple a concept; you scan the 'meter', and that tells your device to connect with the metering company, give it the meter data and your car data, which of course is connected to some account or bill. Perhaps more easily, your car could have a tag on it that the meter reads.
Practical digital subway tokens seem harder to implement.
Note, too, that in the GP post of mine, I noted after my first use of "Microsoft"; (or other service provider). Props to MS and any of the other half dozen companies who have been working on the implementation, but I can still question it's design. Simply put, there are several layers to this; one is the scanning of the image, being able to do it accurately and precisely under a wide variety of conditions. Another is the creation of the tag. Another is using tag data to reach a digital resource.
I'm simply trying to posit that maybe there is no service to be offered here. If the tag can contain a GUID, then software ought to be able to use that to find the resource in question. That software could, in theory, be written by anyone, and have any number of additional features. I see no theoretical reason it needs to talk to a server to achieve this. The server seems extraneous to me. I don't see what function it is providing, and if it is providing none, you don't need to keep anything 'up'. All you have to do is write (and sell) the software that lets you connect a 2D tag to a data resource.
Security wise, well, I could care less. But in theory, MS would know. Of course your ISP also has this data - but in that case it hasn't stated up front it is collecting your data to sell. Google sells it's data, and some people are unhappy about that. It feels wrong somehow, on a gut level. But I'm not sure, as you say, that that is important.
Anyway; I can see your frustration that people are being naysayers, but don't take it out on poor ol' me! I'm with you on the front that the company, regardless of who they are, that can bring this to market is doing something neat. I do, however, see this particular implementation as having an extraneous revenue stream - and by that I mean 'cost to the end user'. With a public protocol the businesses using tags wouldn't need to pay for the server to route traffic. (Assuming that is all it does.) They don't have to increase their prices to the end user. MS isn't doing a service to society in general here, it's generating cash - and it's not clear to me that it's generating it by providing a service to a legitimate need. It's creating a need by wiring the technology a particular way. That doesn't seem cool. *shrug*
Anyway, I think the use of this is pretty comprehensive. Professors can encourage kids to show up to class, because then they get their 'reading material tag', that they scan to see their books on their iPhone. Putting a tag on historical sites is a far less obtrusive way of making data about that site available. You could use a tag as a timecard for sites for which that infrastructure would be cumbersome; the supervisor or whatever just 'takes a photo' of your card, and the phone checks in with the accounting software. School teachers can make sure their kids are all together on their field trips by scanning their tags. Virtual graffiti can be left by having locational tags link to forums. You could use them in third world countries with limited infrastructure (limited bureaucracy tracking you) to identify people, or things that they should get. (Food, medicine, money, what have you.) But mostly I think it would make parking easier. ;)
Anyway, good point; naysaying gets you nowhere. But feel free to take a breath.