RFID is easy and cheap (certainly cheaper than a bar code scanner solution if you have to have to provide both a scanner and a browser device.) and more reliable.
II have implemented a RFID system which we use in Wiltshire (Adam has a copy of the current apk) which runs on cheap android mobiles using NFC tags. The phones we used are the cheapest android phones with NFC (Cost £50/each a year ago, bit more now) and the
tags cost 38p/each and have probably an indefinite life expectancy. Total cost for a year one on the Pewsey Downsaround was 5*£50 (phones) + 5* £10 (minimum amount of airtime) + 350 * £0.38 = £433. Year 2 cost was 5 * £5 airtime = £18 (cheap deal via ebay). Year 3 may be nil if I can remember to turn the phones on every few months (as vodafone have a very low user tariff now). The system paid for its self in one year as it meant we did not need raynet, and they wanted a donation that was greater than the year 1 cost.
The tags are only written at the reception desk, so all the entry desks can register any entrant, as all the phones can look up all the detail on all the entrants. We registered ~250 people in under an hour with 4 desks, with no queues at any time. (I took some
timelapse footage to check how it went and for a fair proportion of the time the people on the desk appeared to have nothing to do. Route and start time are checked and corrected at registration.
The backend is one which means if the phone loses network connectivity it does not matter, and they will automatically sync the data when they regain coverage. It does require coverage to initially login, but that can be done in advance. There is a backup mode if the app has to be started with no coverage.
The system makes extensive use of text to speech (TTS) so people had verbal feedback that the system was working (and entrants appeared to enjoy that the handset registered them by name).
At the final checkpoint the system automatically generated the certificate when they were scanned and it could then be sent straight to the printer to be immediately handed over.
What I found interesting was how it changed how the volunteers on the checkpoints operated. As it was a mobile phone they tended to get up from behind a desk, and in general moved to a point a bit before the checkpoint, this made the checkpoints much simpler as people were scanned before the got to the mass of people at the food. System was simple enough that none of the volunteers had a problem using it (even the most technophobe).
Pic from the end.
The system is deliberately built so it removed the option of a paper backup. I consider paper based system to be very time consuming and almost universally wrong and lacking sufficient accuracy to be fit for purpose. At the PDA this year we had one missed scan, which looking at the screens was obviously one of two people that were walking together.
(If anyone wants a copy of the apk then please ask)