I doubt the Soviets would have intercepted a manned American capsule any more than they would have gone around kidnapping random American citizens or hijacking American ships -- that'd be an act of war.
If the capsule splashed down in an area that the Soviets considered their waters, you can be certain that it would have been considered an "act of war". Things were different during the Cold War.
I think you're forgetting people's mentality during the Cold War and what was at stake. If the worst includes "return the capsule disassembled," that's pretty bad when considered from the mentality that was prevalent during the Cold War, because it would have meant giving the Soviet Union the United States' technology. The lunar program was considered an issue of national security.
I can't tell if you're agreeing with me or if you missed my point. Assuming you missed my point, let me try to elaborate (if not, please excuse my misunderstanding):
I'm not refuting that the USSR would have disassembled, examined, and returned the capsule. I'm pointing out that the US government during the Cold War would have considered that outcome to be a threat to national security. That's what I meant by my statement, "That's pretty bad when considered from the mentality that was prevalent during the Cold War."
From your link: "This was the first time that Western experts were able to get a close look at the aircraft, and it revealed many secrets and surprises. His defection caused a lot of damage to the Soviet Union Air Force." My point was that if the Soviet Union got a hold of one of the USA's space capsules, the outcome for the USA would have been the same that it was for the USSR in the article you linked to.
As I mentioned in one of my other comments in this thread, the space race was part of the larger arms race between the USA and the USSR during the Cold War [1]. Just because the space capsules aren't military equipment, doesn't mean that there weren't serious military ramifications if they fell into the hands of the USSR.
EDIT: Maybe we're talking past each other, because I was replying to a narrow piece of your original comment instead of your comment's intent. I agree with everything you've said: the USSR wouldn't have started a war if the capsule splashed down in their waters, and they would have disassembled and returned the capsule. I'm trying to point out the (perceived at the time) seriousness of the USSR disassembling the capsule. I should have attached my original comment further up the ancestor chain where people were debating how interested the USSR would have been in intercepting the capsule.
It would have been a big deal. All I'm saying is that saying the Russians would have seen it as an act of war is a bit much and gives the Russians too little credit.
The Russians probably would have been somewhat pleased while putting on a show of mild annoyance and the Americans probably would be quite unpleased but unable to do much about it. The MiG 25 thing with the players reversed ( feigning annoyance is out of place with a defection, but would make sense with a technical border issue.) Standard politics.
I am fairly certain the Russians would have recognized that an Apollo capsule landing in their ocean would be a good deal different than a spy plane flying over their country. At the very least they would have known from their own experiance that a reentering capsule would make possibly the worst spy platform ever made.
Consider also that the two space programs were basically all about propoganda. Both countries were more or less on their best behaviour.
That flight was during a period when the Soviet's were terrified of a US first strike.
Not long after this flight was the Able Archer 83 exercise, which is probably the only time since the Cuban Missile crisis that we got close to an actual nuclear war.
> you can be certain that it would have been considered an "act of war"
You should really read up on how touchy-feely Soviets were with all things space-related, and perhaps you would understand how patently idiotic your statement is.