Why did John Moore first become suspicious of Dr. Gold?

When John Moore was diagnosed with a rare form of leukemia, his doctor referred him to David Golde at UCLA for treatment. As part of the standard paperwork, he signed a form saying that the hospital could dispose of his tissue through cremation. Moore had his spleen removed and recovered quickly.

After his procedure, Moore was required to fly to UCLA to receive checkups, which he did for seven years. Eventually, he got tired of the trips and asked Golde to refer him to a local physician. In response, Golde offered to pay for his travel expenses and find him accommodations in a fancy hotel. This offer made Moore suspicious.