[deely3]

By the same logic terms of my current email provider could be changes and all of my emails could become public or selled to higher bidder.

Both Trello and my email provider can do this. Both will have consequences.

[donkeyd]

Exactly, which is why you need to consider this stuff and not use those types of services if you have actual confidential data. Find a provider with clear contracts that prevent these types of changes. Self host. Whatever, just make sure to pay actual attention to what you're doing.