+1 to what RR is saying about nylon.Also Ford's, plastic drain plug is reinforced nylon, will not break down from heat cycling, become brittle .
In order for that drain plug to back out the yellow side tabs have to expand to clear the oil pan tabs. Rapping the plug with safety wire or wire tie would prevent that from being possible. I am not saying it is necessary or that I am thinking about doing it. Just making a comment to those that were concerned. I am not.That sounds right, then you must understand wrapping a wire around a fastener it not real effective .