NIS: AutoBlock Confusion

Hi everyone, i recently checked my NIS history and noticed this rule saying it blocked a computer from accessing mine.

 

Below is a screen shot and i have highlighted the piece of into i am confused about.

 

http://img3.imageshack.us/img3/1138/blockruleux1.jpg

 

It says that if i wish to Protect my computer, i should "Remove" the restriction, and if i wish to allow it access, i should "trust" it.

 

I clearly will not trust it, but how will removing the restriction help me exactly?

 

Will be very greatful for any help on this!