I was told to come here and download a Retuner, which I did. Or at least I THINK I did. I ended up with a PACKAGE file which when I open it it's a bunch of weird symbols, probably a different language (not sure). I put that in my Packages folder with the other mods. Then I read here that the codes I needed to put... somewhere? are the following:

General > By Tunable XML > Sims3.Gameplay.ActorSystems > AlienUtils

• kAbductionBaseChance = 0
• kAbductionSpaceRockBonus = 0
• kAbductionTelescopeBonus = 0

General > By Tunable XML > Sims3.Gameplay.ActorSystems > Alien Utils

• kAlienHouseholdNumMembers = 0
• kAlienHouseholdVisitChanceActive = 0
• kAlienHouseholdVisitChanceActiveHighLTRMod = 0
• kAlienHouseholdVisitChanceActiveSpaceRockMod = 0
• kAlienHouseholdVisitChanceOffspring = 0
• kAlienHouseholdVisitChanceRandom = 0

I haven't bought the Seasons expansion pack for this concern alone, but I tested it out by putting in a code that's supposed to reduce the prices of books in the bookstore. That didn't work so I'm assuming I did something wrong. Can anyone help?

Very well, continuing the thread we began on the EA forums.

Retuner is a script mod. You take the package file you get after downloading and unzipping and put it in Mods\Packages where your other mods are. What it does is expose the game's Master Tuning File to a user interface by way of menus (what its scripting does is create this menu interface). Do not try to open the file.

After loading up the game with Retuner in place, click on City Hall or an in-game computer, then
NRaas > Retuner > Settings > General > By Tunable XML > Sims3.Gameplay.ActorSystems > AlienUtils > kAbductionBaseChance > (and you will see that the default value is 0.01. Change that to 0).

That is the first of the group of three settings changes listed above. Then proceed through the next ones.

I'm not sure you're going to see these particular settings if Seasons is not yet installed, though. And, by the way, alien abductions are not very common things for those of us who never bothered to mod them out as you can see by the default chance being a very small one. My teens do caught up in these if they happen to be up all night sometimes, but I just cancel the silly things out with a DebugEnabler reset on the sims if I see the scenario starting up because I'm not overly fond of the entire concept myself.

Thank you so much! I had to delete the PACKAGE file and put in a fresh one because even after I deleted what I added in there it wasn't showing up at first. But then it showed up and I was able to change all the settings there (without having Seasons installed, FYI).

I feel confident enough now to go ahead and buy the expansion. Thanks a bunch, igazor! Once I've confirmed this has indeed prevented all abductions/visits from those green devils (no offense to any green people who might be reading), I will shout from the mountaintops about how you are the best in the land! Or something. Seriously, thanks again.

Here is the link for the Retuner, if anyone needs it: Retuner