Why was Booth admitted into the presidential box?

[Anita]

I'm not convinced that Booth was in love with Lucy. And, he had already placed her in a difficult situation on Inauguration Day, if he had decided to do something drastic at that time. Any means to an end.

There goes the premis of my new book where Booth escapes from the Garrett's farm, goes to Spain to win Lucy's hand, get's rejected and ends up as a rejected, love stricken, retired house painter in Enid, OKlahoma, where he then joins the circus.

I leave for Spain in a few days. I will check for any trail Booth might have left on his visit there.