Your advice should be made essential reading for all aspiring home business operators. You manage to sumarise in so few points information that costs millions of people millions - if not billions of dollars - in total fraudulent deals.
A scam will always sound too good to be true - but we pursue it believing that somehow we won't be conned. We tend to imagine that we are better than the other people who get conned.
My simple viability test is that if a job or business promised to give you money without your incurring any effort, you should run for the hills. All genuine business is very involving and tiring. The scammers thrive on telling us that somehow we can earn without sweating - hence exploiting our greed and laziness dark longings.