I've had no stringing issues with either pet-g or pet.

Maybe because I don't keep the filament sealed, dunno.
I've put the roll of PET outside under the balcony - where it's open to the elements without actually getting rained on.
To test my: 'it works better after absorbing some moisture' theory.
PET's basically water resistant - so it won't get soggy.
But it was weird that the first 2-300gms were brilliant and then it did start stringing with the exact same settings.
I figure by leaving it outside in a damp uk november, it should accelerate the results I got from 2 years in my workshop - which is not much warmer, but a lot dryer :-)