Should mobile devices be banned in school?
I think the barriers are wider than training and resourcing; teachers are concerned about the 'digital divide' and how to provide for the have nots in BYOD (whilst not fully realising the potential cost savings on 30 machine suites which could be used to resource spare BYODs). I think this is probably more prevalent at primary than secondary schooling. Also the lack of control over content can be a barrier with teachers worrying about not being able to ensure only suitable content is accessed. I have found that equipping staff with iPads or similar which belong to the class as a whole is an encouraging first step in making handheld devices a tool to choose alongside a dictionary or a pen. It also enables teachers and children to 'go and google' (photograph, tweet) similar to use of IT in out of school life. School / home provision partnerships such as parental hiring of school tablets can be a good way to bridge the gap as parents get a good deal on tech they were going to purchase anyway, and teachers get some control over the access and provision of the devices. It's also a good way to disguise 'free school meals' syndrome when children borrow school devices.
I agree that teacher anxiety about a range of issues is a major barrier to moving towards widespread use of mobile devices in schools (yet alone BYO approaches). I have recently had a paper published that (amongst other things) tries to clarify what we mean by BYO (and how it differs to 1:1) - the key point being that BYO may mean that not every child has a device whereas 1:1 involves every child having a device. Our current research seems to indicate that the vast majority of young people, even those from low SES contexts, have access to mobile devices outside school (which is not to say that they would necessarily be allowed, able or willing to bring a mobile device into school on a regular basis).
The issue of controlling the content that pupils access is a difficult one for schools given the requirements upon them to ensure that appropriate measures are in place to protect young people. However, the approach ought in my view to be one of educating young people about the risks associated with Internet use and ways in which to both manage their online data and to deal appropriately with material that is inappropriate etc..
A major challenge for us all is the level of risk aversion within schools and other areas of life.