Add to this that financial institutions have very stringent regulatory requirements about archiving all their communications, including chat and email. Trying

Add to this that financial institutions have very stringent regulatory requirements about archiving all their communications, including chat and email. Trying to game those archives would get them into so much hot water with just about any regulator that I can't really imagine it. Any bank may have dodgy employees that try to game the system. But without institutional support by a multitude of people and departments you could never erase such data. And I just don't see that happening.