traditionally, women can propose to men.
It was considered that as the day also had no legal status, it was reasonable to assume that tradition had no status, so women took advantage of this and proposed to the man they wanted to marry.
A 2 minute Google search gives us this history of Leap Day:
This tradition goes back to an old Irish legend concerning St. Patrick and St. Bridget in the 5th Century. You know St. Bridget. She runs the catholic church in Canton that was used as the southeast district precinct in the Wire. Ya know? Where the had the wire up on Frank Sobatka?
Anyway, St. Bridget petitioned St. Patrick on behalf of all yearning females in that they have a more active role in choosing their husbands. As a result of this request, women were allowed to propose to men once every four years.
So there ya have it. Thank you Google and thank you St. Bridget.
Happy Leap Day everybody!