Advertisers choose their words carefully in order to seem to say far more than they are actually saying. Here’s a good example from a poster I’ve seen on the street recently. It’s for some kind of weight loss cream. The poster has a woman holding the waistband of a pair of jeans that are obviously too large for her. The tagline says
[product] helps you lose up to a dress size
The italics are mine and point out the “weasel words” in the ad. Let’s take them in reverse order.
Firstly, you can lose “up to” a dress size. That’s obviously meaningless. You might lose nothing at all. That’s certainly “up to a dress size”. The advertisers aren’t actually making any claims about their product’s effects at all.
Then there’s that “helps you”. You won’t lose any weight by using this product on its own. You need to do other things in conjunction with this product in order for it to be effective. The ad doesn’t explain what else you might need to do, but I’d guess that something like eating less or taking more exercise might well be on the list.
If anyone is fooled by ads like this then they deserve to waste their money.