You are allowed to spy on other countries only as long as you are really good at it. Sending a random weather balloon to fly over another country definitely doesn't cut it.
You're going to actually have to explain what logic you think you're talking about here in order for that claim to stick. Because no, not even remotely.
Well spying is a crime in most countries so saying that it is not a crime until it's detected is just wrong. My point was that crimes are still crimes even if they are not detected.
Spying on a country, in that country, for another country, is absolutely a crime, not ambiguity there. And spying using satellites, many hundreds of miles above controlled airspace, is not a crime - it's not even considered spying. In between those two you get high altitude spying using surveillance aircraft or balloons. It really does fall in this weird "not a crime until detected" grey area.
The real crime isn't spying but getting caught.