Presumably the thieves are too stupid to either say nothing or say stuff that is true but not incriminating.
It’s been fairly consistently shown that the lasso doesn’t leave you that choice. You can try to resist, but you will fail in seconds and start talking.
Right - I expect that lasso-induced testimony could be easily countered by the defense claiming that the lasso forced them to make a false confession at the behest of the authorities. This argument would actually be a pretty good one because the lasso could be used to compel a false confession - it actually compels obedience, not just honesty.
It would be a far safer approach to use the lasso to get them to give up leads, which could be used as a basis for gathering more solid evidence or to just direct the investigation. “Where’s the girl?” “The warehouse on pier 48. The key’s under the mat” saves you a lot of time looking at piers 1 through 47.
I don’t think there is a problem with magic, per se. It’s the fact that said magic can’t be proven to work. But, like with truth serums, it wouldn’t be difficult to prove that the rope worked. It would no more establish a religion than proving that DNA evidence worked.
That is, if Wonder Woman allowed it to be tested, of course. But I presume this question thinks in Justice League terms with superheroes actually being part of law enforcement in some way. As such, I would think that she would allow that much to be tested. If not right away, then as soon as a big criminal would get away without such proof.
As for my answer to the OP: I don’t know. I think that being interrogated while the police are present would be an investigation, and I would argue that the right to not self-incriminate would require the ability to do so, and thus this would not be allowed. If they say it to someone else (including WW herself), that would be hearsay to bring it up. Sure, confessions are an exception to hearsay rules, but I could see an argument that it’s not really a confession, since it was not voluntary. The one place I’m not sure of is recorded evidence. Does that still count as hearsay?
That is, if the law stayed the same. But I wouldn’t expect it to. The reason for the Amendment is to remove forced confessions from the innocent. But that is not an issue in this case, as the innocent would be compelled to say they were innocent. A secondary aspect is avoiding incriminating yourself of other crimes–which could be dealt with by rules about exactly what is admissible.
With a perfect lie-detecting machine, I just do not think that the public wouldn’t immediately insist that it be allowed as soon as someone who admitted it under the lasso was set free. Especially given the level of power evil can have in that universe.
There’s a reason that the Justice League in effect acts like law enforcement for supervillains.
Does it? Wikipedia said it did pre-crisis. But post-crisis it seems to have lost that power.
Also, IMO, it makes the question too simple. Obviously it wouldn’t be allowed, any more than hypnosis or truth serum, both of which just leave the subject suggestible. It’s more interesting if there is a perfect lie-detector test.
What does that mean?
It doesn’t have to. The police officer is writing down statements.
It doesn’t seem like there is any punishment happening at all, let alone cruel and unusual. The justification for a rope being around them is a civilian arrest.
:eek:
I see no evidence in the movie clip posted by the OP that it was done at the “behest” of anyone.
I don’t see how that’s relevant. They are babbling to a police officer. She is writing it all down. They are giving facts about other people such as who “runs the whole kit” and “he has it all in cold storage, in Crydon.” This is going to help the police.
Safer than what? That appears to be what was going on.
Really? Dang. I just can’t keep up. My vision of Wonder Woman is based in the Linda Carter series. (And she totally used it for mind control there.)
We’re presuming that Wonder Woman wouldn’t allow the lasso to be abused, though, so the mind controlling power would probably mostly be used to get the subjects to submit themselves for arrest without resisting. By which I mean, it usually was. 
After that, of course, the police would have to scramble to come up with some kind of case that stood up independent of this convenient and obviously induced compliance. Fortunately for Wonder Woman their villainy tended to leave some pretty obvious evidence behind - captives, bombs, large swastikas, killer robots…