yeah, after i made that post i looked around some more and found the spider mite discussion.
but then i went and grabbed a 10x lens and a couple of the plants in question and got up close and personal with them under a 100 watt bulb, and frankly didn't see anything. nothing moving, no stippling, but i think i'll crack out the neem oil and spray the collection this weekend anyway.
interestingly enough, the plants that have the webs are the ones i've been misting with worm tea.
i've noticed they also attract a lot more dust than the non misted plants do, so this is something i'll have to consider in the future when spraying.