There's always going to be somebody nosey looking over your shoulder but don't let that paralyse you. Simply take it into account and take action! In fact you can even make use of it.
I'll give you an example. William Schnell, Zone Servant, wrote Thirty Years As A Watchtower Slave. He knew Rutherford's agents were spying and ratting on him. So he used that.
Schnell made a few border-line slightly critical remarks around a person to see if he was snitching. Sure enough it came back on him and then he knew that person was a snitch while others weren't.
A Bethelite or two were following him around. He wrote that he "led them on a merry chase." In other words he wore them out and had more fun doing so than they had in trailing him.
See what I mean? Now if you mean government agents, it threads a fine line between freedom of religion in the U.S. and protecting society which is also required.
I believe that Amazing is essentially correct. Of course things can change as seen with the 9-11 thing. It's been in the news that the CIA and FBI now have enhanced authority and increased ability for surveillance, which is good. (Ro 13:1)