As tempting as it is, according to food safety guidelines you shouldn’t leave rice in the rice cooker for more than 12 hours, even on “keep warm”.
The contamination (spores) come in the rice you buy.
The sarcasm is how I stop myself from getting too angry over the ridiculous US food safety guidelines that discourage people from cooking and encourage waste. Sadly those are treated as gospel all over the Western Internet. I can imagine the comments on TKG...