Q; Why didn't Picard offer in Riker's defence the fact (well established in the series) that the transporter officer, in this case O'Brien, would register a weapon being fired at the moment of transport and that in this instance there was no such register?
A; Dunno, really. In fact, O'Brien can read the presence of weapons in general in transport, let alone when they're being fired, as we've seen before. However, we might assume that Picard in turn assumed that the Tanugans wouldn't be impressed by O'Brien's testimony, perhaps on the grounds that he could hardly be said to be an independent observer. It could further be argued that the unexplained loss of power which O'Brien experienced at the beginning of transport had the effect of temporarily knocking out the sensors, so you could have let a bomb off in the transport beam and no-one would have known.
I'm afraid I can't get my head around Krieger waves and their dos and don'ts at all, so I'm not going to comment on what they may or may not have done. Instead, I'll just point out that at the opening of the show when he was painting (loved the music for this segment), Picard wasn't wearing a communicator. Does this not constitute unusual practice for a starship captain?
Evolution The Ensigns of Command The Survivors Who Watches the
Watchers? The Bonding Booby
Trap The Enemy The Price The Vengeance Factor The Defector The Hunted
The High Ground Deja Q A
Matter of Perspective Yesterday's Enterprise
The Offspring
Sins of the Father Allegiance Captain's Holiday
Tin Man Hollow Pursuits The Most Toys Sarek
Menage á Troi
Transfigurations The Best of Both Worlds
Part One