Who gets to decide that a 360ml bottle of smoothie is 2-3 portions? It's such an obvious loophole to abuse - obviously they don't take the mickey by claiming a bottle is 20 portions but they still seem to have just made up something for the sake of marketing there.
It is, it's very cheeky.
Stuff like this is also particularly bad with children (who are the root cause of the obesity problems) as kids are far less likely to read or care about what the label says, even if it's all red. They'll just eat/drink the entirety of whatever is in the bag/can/bottle. When they get overweight - the food industry will simply point at the label, and absolve itself of any responsibility.