Money is always the driver
If anyone thinks anything other than money is the driver here you're deluding yourself. I'm surprised they:
1. are not charging for holding devices in a 'tablet cloakroom'
2. haven't offered a 'pre-approved' tablet for use in the stadium rental deal (that are the same as those banned less a camera facility)
What happens at one Prem ground soon follows at others - especially where money is involved.