Nice trick for secure e-mail communication

During the last protests in Cairo against preventing "Gaza Freedom March" and "VIVA Palestina" from entering Gaza and building the underground steel wall at the Egyptian-gazan borders, the Egyptian authorities announced that they were spying on the activists' e-mails. That reminded me of a trick was mentioned in "Traitor" movie.

Two or more people can share an e-mail account which they both/all know its password, then anyone of them could access the e-mail, write the message and save as draft without sending it!.Which will be accessible to others who could login to that account.

The idea is simple and ofcourse has drawbacks, but i thought it might help.