Actually, thinking about this - it's not a bad habit to get them into. The gentlemen will have to understand that she requires a serious resource commitment in order to date her.
Dads,
You are the first man your daughter will ever fall in love with. She will learn how to expect to be treated from how you treat her and your wife. Ignore her and she will learn that sex will get the attention she craves from you from the boys around her.