Do people use plastic to make fried food stay crisp?

I’ve heard an urban myth that spreads through e-mails saying that some food vendors selling fried banana/plantain or prepacked fried shallots use plastic straws, plastic bottles in order to maintain the crispness of the food even after some period of time.the plastic will melt in the hot oil and coat the fried food thus gives it extra crisp! Can someone clear this up for me?