Because when people interpret some behavior being done to the legal extent possible, on average they will do so with a poor understanding of the law and their interpretations will assume behavior which is in line with how they think the law works, not how it actually works. While this is their own misunderstanding, it is common enough and exploited purposefully enough that I don't think one can just declare Caveat Emptor (assuming that to buy into something is also a valid translation, which is probably isn't).

For PR it works sufficiently as is. My criticism of the statement is not in its effectiveness and I don't think any resolution of my criticism would allow them to keep the original goal of the statement.