funny story from my limited exp.
Shortly after learning Wayne Houchins Stigmata, I decided to perform at the caf. in my local Community College. I was using the criss cross force and when I asked my spectator to cut the cards, I forgot to demostrate. The guy does the cut and completes it, luckily however, he left a small jog in the deck and i was able to reverse the cut and continue the trick. So you could always look for that.
On another note, when thing that I took from Rich Ferguson(SP?) dvd Tagged, he mentions a way to test and see if your spectator had chosen the word you were trying to force. If they don't, you redo the force by using the line "Just so I can prove there are no gimmicks here, I want you to go back to the pages we were on before....." and re attempt the force.
I've adapted this to card magic, and when I ran into the same issue of my spectaor runing my cut and setup, I run back through the deck and look for my setup, and cutting it back to the top while saying "Now I want to ensure we get a random card so we are going to do it again" and I run a false shuffle to "remix" the cards, while leaving my top stock in place and then starting the trick over.
Hope this helps and sorry for the really long post.
