Tripp was granted immunity from prosecution by Ken Starr. You do not need immunity if everything you do is legal. Tripp's own attorneys felt that her recording was illegal enough to advise her to stop. It is obvious from the tapes that she conspired and colluded with Monica to prevent Tripp from being deposed in court. Finally, she colluded with the Jones attorneys to obstruct justice "make it look hostile". Tripp did violate the law. The OIC granted her immunity because they needed her cooperation.
I am not condemning Tripp, plenty before me have done that. I am condemning those who benefitted from her exploitation and did little to help her afterwards.
You do not need immunity if everything you do is legal. When Clinton is President and Janet Reno is his capo, you certainly do need immunity -- from trumped up charges invented each and every news cycle.
And in general, where there is an suspect "appearance", even only in the deluded public's mind, no matter what the facts, getting immunity is an excellent and wise thing to do.
So Linda Tripp acted excellently and wisely.