Before she drinks the waters (in which G-d's name is erased) they try to
discourage her from going thru the process (unless she is innocent). Bear
in mind that the Sotah DID do something..she violated her husbands orders
not to be secluded with a certain man in front of witnesses. To encourage
her to confess if she actually committed adultery there was therefore an
attempt to disorient her.
To disorient her we tear her clothes, remove people she knows (like servants)
etc. Other woman are required to see this but it is only optional for men to
come. At any rate this is done on Temple grounds and not in the street. Care
is also taken that she not be stripped naked (3:11).
The distinction between total humiliation and "reminding her of how we were
in Egypt so that she should confess" is a subtle one, but it is there
and affects the halacha.
Russell Hendel; Ph.d.;ASA; rhendel @ mcs drexel edu