Comma splices are a bane of my existence, as I’m sure they are for many folks in my line of work. I’ve often wondered why they are so frequent in my students’ papers, and I’m beginning to think they’re an example of the law of unintended consequences.
I seem to recall (and the Spawn confirms) that from grade school on, kids are taught to avoid “short, choppy sentences”, typically by combining them. That’s not a bad idea in theory (and research shows that sentence combining actually seems to work well for teaching beginning/basic/remedial writing), but because apparently the kids don’t learn enough about things like independent and dependent clauses, they’re liable to just stick any two (or more) clauses together with commas. Thus, they think they’ve avoided the dreaded shortchoppy, when in fact they’ve created a spliced (and in some cases a fused or run-on) sentence.
It makes sense to me, anyway, but your thoughts are welcome.