Answer:
If somebody claims a product is the only possible cure, the promised results seem too good to be true, or if its proclaimed to have "special" or "secret ingredients. Then you s=hould suspect quackery.
When should you suspect quackery?
When a product :
- appears and/or is advertised as miraculous/magical
- is mistrusted by experts
- may have questionable diagnostic tests
- contains unknown ingredients
etc.
Explanation:
due to carelessness
.................
Tennis, golf and swimming
