I think it is very interesting to discuss it based on the concept of risk. However, even before considering data sharing, just a look at research funding shows how pretty conservative the whole system is. In a way, maybe this is at the core of the perception of risk in data sharing and open access: if you will be funded in terms of having done the work before being considered to apply for funding, instead of how innovative your ideas are, then holding your own data secure and unknown becomes an obsession: enabling others to base their own ideas and preliminary data on your results becomes giving away a jealously-guarded lead access to resources.