..."stress weed" seeds..??
Any bag seed is a gamble. They most likely weren't 'intintionally' seeded. Meaning steps were probably taken to avoid seeds forming. Accidental pollinations often comes from "rogue" male flowers(hermis).
On the other hand, I grew exclusively from "bag seed" for years, and produced some damn fine product. Bag seed is a great source for seeds, especially for "first grows" or inexperienced newbies. "IMO" choose from "good" sacks, look for mature seeds, and be vigilant for signs of hermophrasism.
Proper care and environmental conditions will yeild a good final product .."in most cases".
if you want to plant a bag seed and want to know if its good squeeze the seed and if it breaks then the seed was no good but if it doesnt its acceptable to plant. dark colored seeds are usually the "strongest".