I don't mean to be depressing, and I don't mean to be alarmist, either--it's not like anybody has to open their MISBs immediately or they'll all fall to dust by the end of the week. My background is in archaeology, so I tend to have a longer-term view on materials preservation than a lot of people (it drives me a little bit nuts when I see comments like "it's been in my display room for 10 years and I haven't noticed any yellowing" or "it's been that way for 30 years and it still looks fine"--sorry, folks, but 30 years isn't a long time in the lives of things, and by the time you're aware of the damage, it's too late). I'm the Collections Manager for a social history museum (as in, I look after our artefact collections--I don't go around trying to collect unpaid loans!), and materials preservation is part of what I do. In that regard, anything that can contribute to the break-down of historic material is something I do my best to avoid--and intimate contact with an acidic or otherwise volatile material is one of those things, even if the Wampa damage is due to glue seepage. That you keep catalogues, instructions, etc. in baggies is good--any food-grade plastic bag will be archivally sound, and makes a good barrier between the collection piece and the acidic cardboard. But, if you've still got them inside the box, then the immediate environment the baggies are in will be acidic from the cardboard off-gassing. It's not a level of acidity that's going to burn your eyes or anything, but over time the effects will build up, and once the damage is done, there's nothing that can be done about it.
I'm not preaching to change anyone's collecting, storage or display habits--if you're comfortable keeping your collections secured in acidic cardboard inserts inside acidic boxes, that's up to you. Same for anyone who displays MOCs in full sunlight. But, my education, professional training and 20+ years' experience tells me it's not the best course of action for long term preservation, and as such, it isn't the way I store my own collection. When discussions like this come up, offering my informed opinion on it is one of the few ways I'm able to contribute to this community! Still, I know of many museums that can't, or choose not to, apply best practices to their preservation efforts; many collectors can't or don't as well (I've still got my instructions in my boxes...and not in baggies!) More information is better than less (or none), so that people can at least be aware of what consequences their decisions might have, and make their decisions accordingly.