Why was Booth admitted into the presidential box?

[RJNorton]

Booth escapes from the Garrett's farm, goes to Spain to win Lucy's hand

I guess this didn't happen then...

("Say the words out loud and you'll know the truth at last. Booth was repeating his lover's name. He said, "Lucy -- Lucy." He moved his dry cracked lips as if to kiss the ring a final time -- and died.")