One of the early comments alluded to this, but didn't quite take it far enough.
If userA leases a drive and fills it with illegal content (child pornography, Snowdon's files, whatever) and then leaves and the hosting company the re-leases the drive to userB without clearing out the drive properly, who gets arrested? Who should get arrested?
userA is long gone. Could potentially be tracked down. Need to prove they put the files there and not userB or hosting company.
userB has access (but potentially not ownership) of said files. This is still arrest-able offence.
Hosting company has ownership of files (possibly) in a leased environment??? If this is the case, should the hosting company be responsible not only for clearing the files from userA before putting userB in jeopardy from the law but also responsible for monitoring their drives for illegal activity and content.
Now we are on a slippery slope...