Not only would you not be "assisting the legal process", you would almost certainly be breaking the law because you'd be denying people access to accounts without any legal authority to do so and without any conclusive evidence of who owns those accounts.

Law enforcement and other investigators already have the power to seek injunctions which restrain MtGox principals from moving BTC from company and/or personal accounts.  They can almost certainly obtain court orders compelling the principals to give them access to those accounts if they deem that to be necessary (and failure to do so under those circumstances would put the principals in contempt and subject to penalties).  The community has not such authority and nor should it.