Mark 12:13
And they sent to him some of the Pharisees and of the Herodians; that they should catch him in his words.
Luke 11:54
Lying in wait for him, and seeking to catch something from his mouth, that they might accuse him.
Matthew 22:15
Then the Pharisees going, consulted among themselves how to insnare him in his speech.
Luke 20:20
And being upon the watch, they sent spies, who should feign themselves just, that they might take hold of him in his words, that they might deliver him up to the authority and power of the governor.
The last one is particularly interesting, as there have been cases of people sneaking in -- literally as spies -- to record events with Bishop Williamson.