Ugh. Who cares? Spy back.

As for going so deep that you marry someone and have kids with them, that's a horrifying and shocking thing to do. But plain-old-cat-and-mouse infiltration...I have a hard time getting upset about that. Information is costly; if you can get it without breaking the law or doing something shockingly bad, go for it. My only big qualification is the government, who ought not be poking around like that. And even then, it all depends. If it's the FBI infiltrating Greenpeace, I think that's scary and bad; if it's the FBI infiltrating a group that meant real harm, I'd be scared if they didn't do it.