All this talk aboud D20 RNG brings me back memories of NWN1 and 2, where the result was hardcoded to always be to your disfavor (for example, always getting hit by an attack of opportunity whenever trying to drink a potion with low HPs, always getting hit with natural 20s when your AC was high and your foes' BAB was too low, etc.), which quite frankly caused huge amounts of RAGE amongst a lot of players. In short...using an RNG to "avoid save scumming"? The problem is that RNGs aren't that random and, what's worse, they can actually encourage save scumming.
As a programmer, I can guarantee everybody here that "random number generators" often aren't "random" at all, and that's because random number generators are based on algorithms. A "random" number generator generates numbers through mathematical formulae and/or precalculated lists, which basically equates to "roll as many dies as needed, write down the results, then assign those result to each and every subsequent roll". In short, they appear random, but are in fact predetermined, that's why they are called "Pseudo-Random Number Generators". Another key feature of PRNGs is that they are periodic - that is, the sequence will eventually repeat itself.
If you want a True Random Number Generator (TRNG), you'd need something to detect natural phenomena and then convert them to die result format, like a radio telescope tuned precisely to the frequency of the Cosmic Microwave Background produced by the Big Bang (since the time between radioactive emissions is truly random), a geiger counter and a numeric counter linked to a radioactive isotope (same as above), a sensor linked to a diode, or something like that. In short, to have an actual random number generator you need a random source (quite easy to find), and a device that doesn't introduce any bias (definitely not easy to find). Obviously, it isn't easy to accomplish with a gamer's computer, and that without even considering things like predetermined, hardcoded results (Like "enemy always acts first") that can easily be put in place. I'm not saying that Larian's developers are that wicked, but it has happened many times with other games, which makes me quite paranoid about it.
What I mean is: RNGs usually put your playthroughs in a predetermined, unavoidable path, and they can be circumvented with relative ease if you know how. You just have to change the variables and save scum until you've gotten the result you wanted.
Examples: someone here has already mentioned XCOM 1 and 2; in order to elude the RNG, having your soldiers move closer/farther enough would usually force the RNG to redo its calculations because the base parameters (distance, accuracy, etc.) have been altered. Save scum until the outcome is to your liking.
Empire total war/Shogun 2 total war/Attila total war: The outcome of agents interactions was usually predetermined. You could save and reload, which usually forced a recalculation of the outcomes, but it worked just once, after which the RNG would save the seed and force the exact same outcome over and over again. A solution to circumvent the problem? Have a very low level agent try any interaction; it will very likely fail, but it will force a recalculation of the RNG, thus giving your top agent another golden chance at wreaking some havoc. Reload/save/reload until the result was to your liking.
The only way to avoid such tricks would be to - you guess it - heavily restrict save scummings, which would bring us back to square 1. The rant is over.
