There have been numerous posts here about carrying firestarters as part of one's EDC. I've been carrying two packages for about 6 months and both have proven effective and reliable. I mostly carry in urban settings or while traveling by car or train and do have to be sensitive about controlled entry to govt. buildings. I haven't had a problem passing thru security checkpoints with either item.
Lots of folks have the 'peanut' lighters. My problem in the past with them, as with most liquid fueled lighters, is that the fluid dries out. I ordered a Delrin CR-123 battery holder and the mini peanut lighter from County Comm. The lighter fits nicely inside, though I added a cotton ball in the bottom of the container to keep the lighter from rattling around. After 6 months of EDC the lighter has retained fluid enough to light easily and produce a reasonable flame.
The other packaging technique is to use the small plastic boxes from CC (just a frequent customer) to hold a mini-Bic and some tinderquick. Tucking the lighter in the case seems to protect it from the gas escaping inadvertently. There's also room for a Sparklite as well.
The peanut lighter has been on my key ring and the mini-Bic in my daypack for about 6 months so this is a good, real world test.
I find that using a fishing swivel really keeps the tops of things from unscrewing themselves, such as pill fobs or the cylindrical battery cases from County Comm.