The truth is that putting the above disclaimers on bottles doesn't really indicate anything about the quality of the oil. I know of many companies who put this on their bottles purely for legal protection reasons. In today's litigious society, I can hardly blame a company for not wanting the liability of potentially losing a lawsuit because someone ingested an excessive amount of essential oil. This has nothing to do with purity or quality.
You can have the highest quality and most pure oil in the world but if you drink a whole bottle of oil, guess what, its going to cause some damage (yes this has happened before). These oils are very good organic solvents and should be respected as such. Is one drop of peppermint oil in your water going to kill you? Of course not. But with more and more people doing crazy things with the oils companies have to protect themselves from uneducated consumers who could potentially abuse the product.