I don't know why there would be 2 passive tags and the radio: I hadn't heard that that's the mix (I'm not sure that any of the technical specs are really public at this time). I expect its 1 passive and 1 active tag, along with a wi-fi device. I think it's something along these lines:
The FCC filing for the device listed it as having two passive tags, one UHF, and one HF. Seperately it references the 2.4GHz radio. See the FCC filings linked from wdwmagic's article here -
http://www.wdwmagic.com/other/fastp...isney-'magic-band'-rfid-bracelet-revealed.htm
A passive RFID doesn't need to be tapped on anything and doesn't require power -- it can be read from several feet away, and is easy to read with some precision when a pair of readers is used. The theft control systems at most major retailers work this way. This is what's most likely used for general guest movement.
Its true that RFID range can be more than just tap distance - it's all based on the design of course. But on an aside, most of those loss prevention systems at retail are not actually RFID - but other radio based technology.. under the umbrella term EAS - See
http://en.wikipedia.org/wiki/Electronic_article_surveillance for a listing of common methods out there. RFID is a successor to these types of systems as RFID is not just 'detection that the tag exists' - but the tag actually carries data that can be read too.
The reason for the different tags is likely different uses. HF is generally looked at as a range of 1m, while UHF tags are looked at as up to 10m. But because they operate on such different frequencies, they have different characteristics when it comes to material interaction (penetration/reflection/etc).
An active system uses power to transmit for some distance. The larger the distance, the more power is required. Transmitting to a distance of 3-6 inches doesn't take very much power, so small batteries could, in theory, last quite a while. This is probably the system they're using for point-of-sale and fast pass returns.
You leave out the important other factor.. frequency
Higher frequency requires more power.. so that's also in the equation on what you use and it's effectiveness. Frequency is also key because it is what determines how the signal interacts with the physical world.
Powered tags are used in part because they improve the response time and the range of tags. But the FCC info describes the RFID tags in use as passive tags - the battery appears to be for the 2.4GHz radio and whatever IC logic is in the band.
The wi-fi is probably a check system -- they can check via wi-fi to ensure that the active RFID is really in the location where the transaction is taking place.
My theory is the active radio is the 'crowd' or proximity feature. The band could be activated by picking up a signal in the area over the air.. and the active radio just sends out it's ID as a 'hey, I'm here' kind of beacon. Then receivers pick up those announcements and can tell how many bands are in the receiver's area. This allows monitoring of larger areas without having irradiate them with higher power RF. Also, the use of a 'trigger' over the air allows the band to automatically shut it's radio off or put itself in a power save state if it hasn't heard a trigger in a period of time.
Then, the passive RFID tags would be used for more specific 'explicit' transactions that require a direct, one-to-one, or explicit consent transaction. Such as point of sale.. player involvement in a game.. etc. These could be close range or explict tap systems.
Or.. it could be as simple as 'the systems we purchased were incompatible..'.. the door locks they wanted to use use HF.. and the POS systems used UHF
Could be as simple as that... but not really possible to say from here at this point in time. Since this is a NEW roll-out.. it probably has more to do with different application needs.
