I think using a phone just opens up so many problems:
1)Most people have a phone...some are App developers...what's stopping them from writing a program to scan and open any door?
2)Plastic cards that have been in use for decades are quite nice...can be out in the sun, water, wallet, etc. Not so much with a phone.
3)Phone out of juice or simply having issues? Have fun.
4)Expanding on #1, the current plastic card systems are proprietary technology and would be far, far less people that have access to the system to hack/break a card/door.
I'm still unclear why a phone (regardless of manufacturer) still has to do 1,000,000 things MORE than a phone. Relying on "the phone" to do everything in your life is...um...that old "all your eggs in 1 basket" mentality.
Ah, c'mon. Don't be such a Luddite. Lots of tasks were done one way in the past but new technology made things more efficient and caused them to be done another way. Isn't that how life and society progresses?
Specifically to your points:
1) I would think any company offering phones as a key would be cognizant of security issues and legal liability. Also this kind of keyless tech has been available in cars for a few years now with no huge issues I know of. The difference here is that the user uses a phone rather than a FOB.
2) When I'm at the beach or pool I have my phone with me. In fact the only time I don't have my phone around is when I'm in the shower. I see plenty of phones at the beach and pool, just not IN them. But also I doubt the phone as key will be mandatory, just and option.
3) Yes, phones run out of juice, but you are at a hotel, staffed by human beings, not left on a deserted island. Haven't you ever locked yourself out of your hotel room or lost your key? You go to the front desk and they help you. I don't think this tech means they won't have a way to get in your room. Maid service, for example, still needs a master "key".
Generally, I think this is a great idea. No check in, no wasted plastic, no lost keys. I think the twist thing is a little hokey, but that's probably for video demo, not real life. Sure, its not perfect. Nothing designed by humans is, but no need to go into Dana Carvey's Gumpy Old Man routine.
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If i'm at a beach hotel, I leave my phone in the room because I don't want it laying out or hidden in 80+ degree weather, with sand, and possible water nearby. I also don't want it stolen when I go into the ocean.
1) Zip lock bags work great.
2) Go to better beaches. I've never feared my phone being stolen.
3) I doubt the iPhone as key will be mandatory, just an option.