No warnings in Jack's latest post, however please note
"The  script which triggers the warning is not present 100% of the time.  The purveyor of the script limits the number of successful downloads to a computer, therefore the link can be clean, next day or a minute or hour later may contain the potentially dangerous script."
He obviously pays for just so many successful insertions in a set period, and he expects to recoup this expense.

See what others say regarding Popunders

https://www.bitdefender.com/consumer/support/answer/2574/  or 

https://hitprobe.com/what-is/pop-under-ads

And should you reward a spammer who has destroyed 23 UseNet groups. ? These groups now consists only jacks spamming samples and his potentially dangerous link to Filedot 

Prior to Jacks arrival ,some were relatively quiet but some were  thriving communities.  Now thanks to Jack all are dead.  He is the only poster.

Finally. :-
If you follow his links you will be complicit in destroying the Usenet

And you may end up with a nasty script