Lennier has no such power; Delenn chose to tell Lennier not to mention
that she was a member of the Grey Council. With Sinclair, Lennier was totally
unaware of Jha'dur's time with the Windswords when it was first mentioned to
him. He then went and spoke to Delenn and the Council, which explained the
situation to him, and gave him his marching orders. He did not get Sinclair
to "chat about top-secret information," Sinclair came to him to find out what
he could about Jha'dur's claim.

jms