As anyone thirsty going to the airport knows, the TSA enforces a 3.4 ounce limit on liquids going through security. What is the rationale for this?
Aside from enterprising businesses that have the 3.4 oz containers (enjoy!) on Amazon SEO optimized, the first response from Google is a 2009 blog post from the TSA explaining the lineage.
3 ounces was the first limit promoted, but that wasn’t the actual limit, which was 3.4, or 100 milliliters, the European stricture the TSA wanted to align with. 3 was easier to remember than 3.4. This would have been easier, TSA employee “Bob” opines, if we had switched to the metric system. They started to communicate the 3.4 instead of 3 anyway.
Pop quiz: name anything in your life that is 3.2 fluid ounces.
Like 3, 4 is easier to remember than 3.4. The “Why” of any limit is never communicated. What is it about 3.4 ounces that is safe, that 102 ml is not? What makes 108 milliliters a gaping security hole?
Of course, this isn’t a limit at all. Anything you want to smuggle north of 3.4 fluid ounces is given a guide: Medications, baby formula etc. all can get through. Devoted terrorists ready to use a liquids-on-the-plane approach to destruction are given a roadmap on how to circumvent it, while you’re throwing out your perrier.
All 3.4 ounces conveys is just that citizens are supposed to blindly obey the in faux Orwellian, ineffective state.