I feel like I'm the only person who doesn't get liners, lol. My hedgie seems to prefer shavings.
That being said, I used CareFresh for upwards of 2 years when I had rats, and never had a problem with mites. I think a lot of it depends on how that particular pet store stores their bags before putting them on the shelf. I'm sorry you had a bad experience, though - it's awful when you know your pets are suffering.