Mary Surratt and John Lloyd

[Gene C]

Supposition,
As I understand it, the conspirators did not know their fate until 24-36 hours? before the hanging.
The good folks hiding John tell him his mother is in no danger. He believes them. By the time he learns of the death sentence, it's to late for him to do anything about it - he's hiding in Canada. He admitted in his lectures that even had he known she was in danger, there was nothing he could do to save her (so why come out of hiding, it would have served her no purpose - his reasoning, not mine).

No doubt in my mind the Gov't was trying to lure him out of hiding. No hard evidence to that effect that I know of.
I think Anna was arrested, but released. (I recommend Kate Clifford Larson's book, "Assassins Accomplice", if you haven't already read it)