Save money lying on the specs. That's fraud.
Ignorance. This is almost as bad as the first one. It just reveals that they are incompetent. Incompetent or negligent. How somebody can shrugh their shoulders at this incompetence is behind my comprehension.
Then there is the aspect of the money.
"it's a cheap bass, who cares".
Well, I have news for you. A bass that costs 350-400€ is not a cheap bass. At least in the real world, it's not.
That's a lot of money. That's half of a salary, in my country. A EU country.
Laws don't often align directly with emotions. If they did we'd be in big trouble. Like many others have said, there's boilerplate clauses that let them make changes to their productions regardless of what the advertising copy says. Those sorts of things in manufacturing of consumer goods are almost always rock-solid.