ecan6 & RottenRiley - I appreciate your lines of reasoning. Here are some thoughts to consider regarding this particular situation.
The leadership of the Watchtower believes that they represent god on earth. They know that they are speaking the truth but, as we all know, the 'truth' is adjustable. They believe that they are going to heaven to rule with christ over the earth. They believe that this organization is mankinds only hope for a successful and happy future. They tell you that the money is needed for building projects, support of full time staff and travelling representatives, and for the production of literature. No deception here. In their minds (and in yours when you gave your money away) giving freely shows that you are a good christian.
They are like the Wizard of Oz - the man behind the curtain. The difference is that the GB believes that the scary, smoky 'wizard' that they operate is real. They are 100% in. They are not deceiving you when they ask for donations - god needs this money. In their minds, you gave back money to god by donating it to the organization.
Proving deceptive practices in a court of law is possible. Proving unethical behavior is much more difficult.
ginger