I believe they should know where the money goes. Not specifics, but definitely what the total intake was, what percentage was given out to the community, and maybe even the highest employees salaries if they exceed a certain percentage of the intake.
Disclosure keeps everything honest, and while I know the vast majority of frum charities have nothing to worry about compared to other non-profits, it is still important to be seen as honest. If a company is managing their money poorly, I would rather give to a charity where I know the community is benefiting.