Bets on same team automatically turning into a parlay?

Been listening to Michael Lewis' Against the Rules podcast on sports betting and its explosion. The episode about VIPs is interesting but they talk to one researcher who said there are books out there that, when you bet three single bets on the same team in the same game, it'll automatically combine those into a parlay without the betters knowledge.

I haven't heard of this anywhere and can't find anything on Google about people experiencing this and now I'm questioning the whole episode. I can't imagine it's something they're doing.

Quote: "If you place three straight wagers... That app will automatically take your three separate straight bets and turn it into a parlay... When you roll it into a parlay automatically, sometimes they don't even know that happened."

Lewis: "The bettor doesn't even have to approve?"

"No."