There are several reasons for this: firstly, sneakernets can generally provide very high security (and possibly more importantly, they are "perceived" to be secure) due to the impossibility of a Man-in-the-middle attack or packet sniffing; secondly, the volumes of data concerned are often extremely high; and thirdly, setting up secure network links between the client business and the analytics team's facilities is often either impossible or an extremely convoluted process.