What's the "dangerous" aspect of lighters? The lighter fluid? Will the TSA today even routinely, readily and quickly identify that as being distinct from water or any other liquid poured into a more mundane-looking bottle? The answer is that the TSA would more often than not miss it.

Someone pouring lighter fluid into a bottle and keeping that and a few other items in bag, and a de facto lighter can be readily put together airside without the TSA being any wiser or the plane being put at any seriously greater risk.

This is just another stupid, ineffective restriction vis-a-vis terrorists. All this restriction does is inconvenience the innocent traveling public, enrich matchmakers and lighter salespersons, and make "criminals" of those who may have some personal need for a lighter and just pocket the thing while walking through the security checkpoint.