Re: arrested for not testifying?
Well the thing about this is, if you weren't to testify it would be viewed by the law as wasting police time, because a conviction can't be made without you testifying, so therefore police time has been wasted and justice hasn't been carried out.
Also I presume that its a court situation because you are testifying so it could be seen as a contempt of court. And judges get really pissed at that.
I would be of the opinion that people should be made to testify in these situations because it ensures justice can be carried out, otherwise you have situation where if the person you are testifying against can threaten you, you say you don't want to proceed, they get away with it and justice isn't carried out.