I agree NFC would be more secure. I work in IT and we often have to rollout technologies that may not be the best solution, but we have to be careful not to sisenfranchise certain groups of users, such as those with older phones and browsers. The range of BT actually contributed to one of the issues I had at the hotel. As I was nearing my room the button turned green and right as I went to push it, it turned grey. Once I hit the button while grey, the app would not work no matter what until the front desk resent a new actuvation code. I am guessing they ar using a code hopping technology that has trouble stncing after missing part of the algorithm. We used to see this in some of the early car alarms and garage openers with rolling codes. NFC could force people to rest their phone on a pad on the door.