I've had the mineral oil Fleet enemas too... Let's just say that I'm not too sure that I'd want to try 4qt. of that stuff unless I planned to be home bound for several days and near a toilet.
The last time I had a Fleet mineral oil enema I had three clean out enemas after that... I had been with a friend, and I survived a nearly 3 hour drive home without any sort of accident. Next day I was still okay, even while passing gas, and had no other noticeable leakage. The next day, Monday morning, I was pretty certain that the clean out enemas had did their job amazingly well and had no worries whatsoever about going to work that day.
And I was fine, the entire day - that is until later that day and near quitting time. I was (fortunately) in the restroom pissing in the urinal when I tried to pass what felt like a little gas... Then felt that small "pool" ooze out instead. At that point I instantly clenched my cheeks, precariously holding the oil suspended there as I hobbled towards a stall and got inside dropping my still opened pants immediately and planted my ass on the toilet.
I inspected my shorts and thanked gawd there was no "spot." I had tried to push more oil out while I sat there, but I didn't feel any more exit, oil or anything else. I wiped my butt and a slightly-tan thick oily residue was all that was on the paper. I thanked gawd again that it was nearly time to go home, and that there had not been anyone else in the restroom when this had happened, lol.
I had no other hints or reminders of that particular oil enema after that.. I surmise that a small "pool" of oil must have sat in a fold high up someplace then had managed to creep out after a couple of days.
I am not a diaper fan... But if I was to try to take a 4qt. mineral oil enema, even if I had several clean out enemas, and even if I had them given to me over the course of several days too, I'd be wearing a diaper until at least 24 hours after I had seen the last oil.
And, you will see the oil... Like others have mentioned, oil enemas will leave a tell-tale mess in your toilet. With me, I leave oil droplets in the toilet that are hard to flush away because they float so well on the water.