It’s like saying “Hey, wanna study together at that coffee shop?” Then using what should’ve been a harmless study session as a date. Typically during dates you’ll ask personal questions to get to know the person better and talk about yourself. All topics that rarely come up during study. Of course there’s more nuance to it, asking someone about their interests isn’t always ghost dating. Frankly OP could’ve been ghost dating this girl. We don’t know anything other than him paying for her drink. It’s one of those things that’s hard to define, but you know it when you see it. There’s tons of room for overlap between the events of a date and a study session.