I think popeye would be a case of reading too much into it. Another obvious scooby plug was in one of the live action movies they made. I remember some comment about shaggy stating they stay away from places that have the word evil in the title. Evil and hydroponics....but for other reasons. I think they even meet a chic named Mary Jane and drool all over her. I'm sure my wording is off, I can't remember much about the movie, but I remembered that.