It really depends on what's offered or used for. Indeed two people can use one blackberry, but it will be tied on one account. It really just depends. If it's an account tied to an exchange/domino/groupwise BES server, then enterprise activation can only occur on one account , one blackberry. So unless it's a common account (i.e. lets say like a
email that everyone uses) then yes, otherwise, you can attach two BIS emails. This in turn will also be useful for the two (though contacts and calendar will be the same)
So it really does depend on what they need.
Hope you can understand and if this was helpful