Uh… no. “Illegal,” recordings are, by definition, NOT LEGAL - nor admissible. (Face palm.)
Recordings which include many, many many people, openly discussing things in a location where anyone could hear them- and they know that, do not meet the 4th A’s “reasonableness,” clause. Even though the 4th A mostly pertains to Search & Seizure, it’s two clauses are 1.) Reasonableness 2.) Warrant clause, the element of “reasonableness,” is covered here, too.
No, I don’t need to have been part of the conversation to make the recordings “legal.” That said, we, ourselves can be heard in the recordings as we also were well in range to be heard. Wide, open areas where anyone could be at anytime, kind of eviscerate any “reasonable expectation of privacy.” I forgot the case name, but, this was very specifically covered by SCOTUS in a case which involved people sitting in a booth at a restaurant. Is there a “reasonable expectation of privacy,” to not be overheard, sitting in a busy restaurant, but in a booth? In that case, (and @mbdsea can help if she/he remembers this case & so wishes to jog my memory 
)I believe the ruling favored the defendant. The dissenting opinions (as I recall) were just as interesting a read.
In any case, regarding your allusion to civil suits, those plotting a murder & other acts of violence had better be able to prove their voices were cloned by imposters & were not in fact, they , themselves doing the speaking. These individuals happen to have extremely distinct voices- and their intentions were very clear. Again, they will be released. To the media, to the gen pub and on all sm platforms if for ANY reason they’re suppressed. Unless, those who are already investigating (besides the criminal court & my own civil lawyers) advise me against this move. If this occurs, I will be fine with it, as I’ll know (at that point) the contents of the recordings will produce bans from the sport.
FYI- your saying of the words “illegal recordings,” doesn’t make this so. But, keep trying!
