Might be cheaper but we are witnessing the defendents rights at any cost as it is...she could sequester them now.
A jury can't be sequestered willy nilly.
A defendant has to show
good cause why it is reasonable to presume that (a) jurors are exposing themselves to prejudicial information
AND (b) that they are being influenced by that information.
OR
Demonstrate that media reports, etc., are having an
actual impact on the trial.
Both standards are very difficult to meet, which is why Judge Stephens has denied previous motions for sequestering and media blackouts. The current media blackout is based on the alleged effect on witnesses, not jurors.
Of course this makes it all the more perplexing why there's a blackout for Arias' testimony (if Arias really is the secret witness). I can only guess that, in true Arias style, she's blackmailed the court - if JSS won't let her testify in private she won't testify at all, which will be tantamount to denying her right to present mitigating circumstances.
It's equivalent to her real world MO, where she corners people, away from prying eyes and ears, to tell them her lies. Except that this isn't a house party, or camping trip. It's a court of law, with 12 people who are going to end up comparing notes. And one of their big questions is going to be, why the secrecy?
Luckily, Juan is going to ask the same question.