I've seen these before, but can't see how you would leave it unscooped even 1 day never mind 7!
And if you DID scoop what would be the point of having it anyway, you might just as well use an ordinary tray. The only difference is you'd have to wash an ordinary tray whereas you just throw the katpak tray away.
I like where they say how it is better for the environment - I don't think so! So its made of paper and will degrade - while plastic trays will take years to degrade - well if you use a plastic tray, chance are your'e not going to throw it away for years anway, but think how many of those katpak trays you'll be throwing away in a year! (well, how many I'd be throwing away anyway!)