Obviously whatever effect meditation has on seizures isn't universal among people with epilepsy, or there wouldn't be controversy about whether or not it's real. It's also true that stress is a seizure trigger for a whole lot of people, and that insofar as meditation reduces stress, it might be expected to reduce seizures. Here's a link
to a clinical trial exploring this hypothesis. As far as I can tell, whether either effect exists and which is larger is not currently known. It's entirely possible that for those of us with epilepsy, not meditating is indeed more dangerous than meditating.
I'm hardly an expert on this stuff, but for anyone interested in looking at what's known, here is a link
to what feels to me like a pretty balanced discussion, and here's an abstract in pubmed
from a paper arguing that meditation might predispose to seizures. All this is pretty preliminary, and there certainly hasn't been enough work done to discriminate among different types of meditation.
As I say, I think the jury is still out on this, but as a beginning meditator and who also has seizures (but for whom there is no connection between the two), I was surprised and interested to find both experts who think that meditation might help seizure control and experts who think meditation may be harmful to some people with epilepsy.
Again, I'm sure the effect can't be very large. We discussed this a year or so ago on the Epilepsy Foundation of America's web board, and as I recall, nobody there felt that meditation had had either positive or negative effects on their seizures.