
They are saying that Smart are working on behalf of 'the owners', but obviously do not state who 'the owners' are.
The next sentence states that 'vehicles are left at owner's risk'.
My understanding of those two sentences taken together is that the owners of the car park are accepting the risk of harm being done to vehicles. Especially when one considers how ambiguity is resolved with s69 of CRA2015.
*that 'cause for concern' being one for the car park owner of course.