Hmmm.. I'm not so inclined to think this is bogus. I'm not familiar with GSE for this, but I suspect it could work. You'd want to know how long it takes.

It's fair to note that you can sanitize your water by just filling a clear plastic bottle and setting it in the sun for a hour or two. Sunlight will kill all the nasties in there. It might taste like crap though. And I'm pretty sure lime juice will kill the nasties too, so yeah, there are alternatives to iodine and chlorine.

Here, in most places I just use a charcoal filter (Britta squeeze bottle), but we have really good water here, and lots of it where I generally hike. I've never been bitten doing that here.

Texas, that's a different story. At the least, I'd charcoal filter the water and then boil or Sun sanitize it. You might want to filter it more than once depending on the source. A coffee filter is a good pre-filter. Some people use a bandana. I'd think the coffee filter should work better, but the bandana is multi-purpose, so there's your trade off.

I'll mention for the record that as a rule, if you can, you want to collect running water, not standing water like in a pond or lake, or still spots along the bank of a creek or river.