There is a laxative product that is commonly prescribed to childhood cancer patients that is just polyethylene glycol. You take about a teaspoon of plastic micropellets and stir them up in a glass of water and drink it.
I think we'd be a bit more disturbed if teenagers accidentally ingested the teaspoon full of plastic whilst going about their daily lives and eating their regular diet, especially if the plastic wasn't designed in a way which made it easily pass through the gut.
The PEG used for medicine has very short chain lengths, and I would be surprised if it isn't liquid or water-soluble, and not taken in the form of actual micropellets.