That's more than a little spooky. Surely those kind of odds are beyond lottery odds?
If I ever went again, I would (because I have actually thought of this before) make sure there was some dollars kind of on show (to the person doing the massage) on me, but hidden from the guards. Give her the nod, she takes the loot, hides it, and then at the end I make a note of publicly tipping her again. That gets taken off her by the prison officers but she gets to keep the hidden stuff. You can buy what you like from the prison officers.*
* In some of the South American prisons the prisoners are armed with guns and grenades, and occasionally it kicks off between gangs. .
You probably already knew most of all that already.
I only saw the latter 3, Michael Kiwanuka was ok, nothing special, Simz I absolutely loved and Coldplay, while being the big entertaining spectacle and the crowd singing their hearts out was a treat it was the weakest of the 4 times I've seen them. I'm still happy to have watched them, they are always a feel good fun time and pull out all the stops to deliver a visual spectacular alongside the tunes.