Fairly simple plugin that I was suprised didn't exist already(or at least I couldn't find one).
Allows you to set a target(s) to be invisible to sentry targetting(You can still be manually hit with the wrangler, obviously).
sm_sentryimmunity <target> <0/1> -Slay Flag
sm_sentryimmunity Thetarget 1 - give Thetarget immunity
sm_sentryimmunity @me 1 - give yourself immunity
sm_sentryimmunity @humans 1 - give humans immunity
sm_sentryimmunity @bots 1 - give bots immunity
sm_sentryimmunity @red 1 - give red team immunity
sm_sentryimmunity @blue 1 - give blue team immunity
sm_sentryimmunity @all 1 - give everyone immunity
sm_sentryimmunity @!me 0 - remove immunity for everyone but yourself
sm_sentryimmunity_chat "1" - Enable/Disable(1/0) Showing Sentry Immunity changes in chat
sm_sentryimmunity_log "1"- Enable/Disable(1/0) Logging of Sentry Immunity changes
sm_sentryimmunity_all "0" - Enable/Disable(1/0) Sentry Immunity for everyone
Version 1.0.0 - February 23, 2011
* Initial release.
Version 1.0.1 - February 24, 2011
* Small coding change.
Version 1.1.0 - April 17, 2001
* Coding change to make use of new SetEntityFlags function.
Version 1.1.1 - April 25, 2001
* By request, added a cvar to allow immunity for everyone at all times