The Hardtops leak as well- live in a wet country and you'd realise that, - I have both soft and hard top.
The Wiper tray that Kane/evil was talking about, shouldn't fill up, there is a more than adequate drain at the bottom of it, it helps if the pipe isn't folded back on itself (some have found this after a service!)
The top of the tray itself can suffer leaks due to capillery creep, it was just a simple job to drop the tray apply sealant at join, lift tray and tighten, wipe excess sealant off, seal all screw holes and screws individually. - mine wasn't leaking and I am on the original SAM unit ( the car is five next month!) but while I was having a look around the car I thought what the heck it can't hurt.