However they have a gentleman’s agreement to not do that.

Trying to remember back to Snowden, I think I recall that not only DON'T they have such an agreement, but the intelligence folks consider this a feature. The US government is Constitutionally forbidden from reading "US persons" communications, but our Constitution has no such restriction on third parties. So if those third parties do the spying for us, and then tell our intelligence folks about it, everybody wins. Well, except for the people.