Actually, I have conferred with people who understand coding (I know zilch) and I found out that it would be entirely possible to program the popup (at gator’s, not here) to appear when the the board script is requested, so it would pop up exactly when someone wants to enter the forum, which is what happened to mstgr. That would make it look like you had to download it in order to get in.
However, I have tried this a number of times and nothing happened.
I must add that there are so many gator type programs out there today that mstgr and janet could easily be infected with something that didn’t show with simple testing.