That's why I advocate bringing tipping to nz. Service people should provide good service, not matter how much they are paid. Whether they like it or not, THEY are the face of the business they work for.
I disagree with you, Alan, I think stores have a duty to provide solid advice. Just because they don't, doesn't mean they shouldn't. Imagine you were to buy a car. You want one that will seat your family of 4, fit in your garage and be able to tow a boat. You ask the sales person for advice. Were they to sell you a ferarri, you would have the right to get your money back, and depending on the situation, sue for damages because they have breached the fair trading act. However, you really wouldn't expect that; you expect that people selling cars or houses or tvs know their products and will advise you accordingly.
Pet stores have the same onus of duty of care. If you ask them for advice and they misrepresent something, they have breached the fair trading act. I think petstores truly have a duty to learn their products and to provide solid advice. If tipping is that way to encourage and enforce that, then i'm all for it.