England have wished New Zealand "good luck" after suggesting they have spied on one of Eddie Jones' training sessions.
Jones was overseeing an important team run ahead of Saturday's World Cup semi-final when an unidentified cameraman was spotted in one of the residential buildings overlooking the pitch.
England, who have Prince Harry's former close protection officers as part of their security detail, investigated the scene at their Tokyo training base after seeing a suspicious red light.
Defence coach John Mitchell pointed the finger at New Zealand but sees little value on spying on the opposition.
"If that is what they want to do, and that is the way they want to prepare, good luck to them," the former All Blacks boss said.
"We just happened to be training where there are apartments above our tiny two-metre fence was, so I am not sure about what the use of the tarpaulins are.
"The facilities have been excellent but it's an area where people live and there is the odd red light around. There was one up in the corner, which was a bit suspicious.
"It doesn't really worry me. This game is so dynamic now so I don't see any advantage in spying on a team.
"When I took over the All Blacks in 2001 we had a manager who was highly military and he loved surveying the whole area.
"To me, you can get too involved in it and create an anxiety on your group. There is enough pressure at this level without chasing around some blokes that might be in a building with a camera.
"I was with Sir Clive Woodward when we were going for a grand slam against Scotland and we chased somebody from one of the papers around the corner and caught him in a hedge.
"He was pretty unlucky actually but that was when the game was a lot different to what it is now.
"I've seen coaches spy, I've had other coaches spy. I've had mates spy as well and it is, but I don't see any advantage."
Jones shrugged off the incident as the biggest match of his four-year reign looms.
"There was definitely someone in the apartment block filming, but it might have been a Japanese fan. We don't care, mate," Jones said.
"We knew about it from the start, it doesn't change anything. We love it."
After initially joking that England had sent someone to spy on New Zealand, Jones agreed with Mitchell that observing another team in secret no longer has any value.
"I haven't done it since 2001, used to do it. You just don't need to do it any more, you can see everything," Jones said.
"You can watch everyone's training on YouTube. There's no value in doing that sort of thing, absolutely zero.
"Everyone knows what everyone does there are no surprises in world rugby any more that's the great thing about the game you just have to be good enough on the day."
New Zealand enter the match as firm favourites but Anthony Watson insists the experience of England's contingent on the 2017 Lions tour proves they are not invincible.
"Even before that tour I respected how successful the All Blacks had been for a long time but they're humans at the end of the day," who was part of the drawn Test series.
"There will be 23 of them and 23 of us on Saturday and they're human beings and rugby players just like us.
"I believe I had that mindset before: that they were beatable. England came close to beating them in November as well."