Many people don't appreciate the wizardry that goes into making a shelf stable food product that will look appetizing and be safe for consumption - after weeks, or months or even years on a shelf in a non-airconditioned grocery.
Take syneresis - the expulsion of liquid from a gel (syneresis is what makes cheese separate from the whey which is expelled from the milk). Now say you want to make a shelf stable Jelly - Gelatin tends to undergo syneresis after a while (leave a home made Jelly in the fridge and it'll end up in a puddle), or a yogurt from cow's milk which doesn't have enough protein (and hence becomes a jelly like "yogurt-ish" thing - that BTW - usually has whey on top since Syneresis continues).
So you'll need to stabilize the gel. Adding more Gelatin will help (as will adding NFMS - Non-Fat-Milk-Solids to cow milk for Yogurt). Or you can add binders (water "glues" - or hydrocolloids) like flour, or carrageenan (think Danaone Yogurt), or Gellan, or Pectin - or usually - since each these will impart an unwanted flavor to the Gel if too much is used - a long list of these - each in a very small undetectable amount.
Some of these may have additional binders. Or agents that help them dissolve. Some - like Gellan - will become a snot like suspension in a liquid. It has to be powerfully sprayed into a liquid to disperse well. Try to mix corn starch into hot water and see how difficult it is to dissolve the lumps. Luckily for corn starch - it has no problem with cold water.
Or take a Snickers bar in a gas station... Shone on by sunlight during the day, cooled down at night. They melt - but unlike chocolate - keep its shape. In the past we'd know it underwent heating an cooling by the cocoa butter separating as a whitish sheen on the bar. I think they solved that. How - I don't know. My guess is something the stabilizes the chocolate emulsion. Also, when you see CMCs, those are cool - they harden when heated. Most hydrocolloids soften or melt when heated. If the food technologist wants something to remain stable when heated - CMC (a cellulose gum) will harden when heated. Great for that Snickers bar!
Many suppliers of these starches (companies like ADM, Cargill, American Starch, Ajinomoto, CP Kelco and many others) can sell the base product (e.g. Carrageenan Iota or Kappa, Acacia or Carob bean gums, Pectin) or sell a proprietary mix - (e.g. Stab 2000 from Louis Francois a manufacturer in France) - If it is proprietary - what does it contain - does it contain gluten?
So when I look at a "bag of (simple) chips" - I don't believe them. For example - how is the oil stabilized? What prevents it from going rancid? Nitrogen in the packaging helps. As does the air and UV tight modern (annoying to open) film bags. But still. Try to taste a day old chips - and it had better days... Usually they add anti-oxidants, which absorb the radicals without becoming free radicals themselves. Where are they in the ingredients list? Probably too low a concentration so that they have to be disclosed. In Japan, you'll usually find a tiny bag of oxygen scavenger (usually activated charcoal) that absorbs any spare oxygen that gets in... Like a getter in a vacuum tube. In Europe the regulators don't trust you to not eat the scavenger so it has to be in the food!
So being able to mark "Gluten Free" is really tracing back the sources in a food safety compliant way. It is hard work in any case in the modern technology heavy world. Definitely not a "marketing" logo in the sense of "stating the obvious" - but more in declaring the "this bag of chips is designed to suitable for a larger crowd than most other chips" - we are auditing our supply chain to ensure that indeed - no flour is used in making this product. The other chips may or may not have gluten - caveat emptor.