I hate to nitpick here but "caramel" isn't exactly a great comparison for oil! Haha! If you cook with caramel, you know it's thick, very sticky, doesn't flow well and break apart in dollops rather than a smooth flow of liquid.
Anyway, this is quite a crafty tactic on Shells part. The warranty brings in the users and the constant reminders makes sure they stay as users.
How often is any engine failure an oil related failure?
- Oil starvation - isn't the oils fault
- Oil boiling to oblivion (probably due to track use) - grey area
Apart from fake/recycled oils, any oil in the market even the crappy cheap oils will lubricate enough to let your engine run without much issues. And considering how long Shell has been in the market, their oil formula isn't going to ruin anything unless abused, which in case will void the warranty.
So it's a win-win for Shell. Crafy indeed.