It was No. 4 and I did make that suggestion with the shot of Indy with the gun pointed at her private parts (though someone else provided the screencap).
Found a thread on the topic :
http://raven.theraider.net/showthread.php?t=8879 . Can't find the one with the screen cap yet.
In any case, I will state my case as to why they did it. Indy's gun is pointed "there", and as Indy loads and pulls back, the gun has gotten longer for that moment and pulls back. That's the moment Marion wakes up. Gun= Indy's other "whip."
Simple semiotics in screen analysis.
Yeah it is true that the Black novel and the comic doesn't imply that, but think of the audience who would read those books. 10 years and up, I reckon. You're not exactly going to put sex in there (however, there is that scene in the novel at Sallah's, where Indy feels tempted and tries to seduce her and she wants to sleep, talk about irony! And that reads a lot more steamy because you're reading Indy's thoughts and feelings). And even, after reading that scene in the book, it makes you more likely to believe that they did it on the boat. Just my two cents.