Have the light taken apart, head with tailcap, and the two tubes nice and empty, or filled with something soft like say socks, facing up when the bag is laying down on the conveyor so they can see right through them on the xray. Batteries separate in plastic clear boxes, light battery carriers also separate, and empty.
The big problem where lights are concerned is as Teej mentioned, they don't want to see anything that's big enough to be a club, which a TK75 flashlight, especially with an extension, would qualify as. Taken apart in pieces, and odds are you won't have an issue. While it's great having that extension... consider not taking it, and just the second second set, or altogether another set of batteries instead.
Same goes for the laser... there are no rules afaik for having a flashlight host, heatsink, driver, and lens, all in nice separate pieces. Keep the lens completely separate on the off chance that you get an extra intelligent and zealous tsa agent who decides to try to put it together and succeeds... less chance of him blinding himself or others.
The second big red flag to them would be anything that they don't understand/or that looks complicated. Keep things taken apart in pieces, and odds are you won't have any problems. Flashlights at least are 100% legal, so it's not like you have anything to hide. Lasers, I'm not sure about. You can take comfort (lol) in the fact that TSA recently failed in 95% of security checks.
I did fly out of newark with a TN31 in my carry on back in 2013 without any issues (and that's a pretty big light) but I was also very early for the flight, and would have checked it if they had an issue with it. Or mailed it to myself for that matter. No way I'm giving some grubby handed TSA agent a $150 light as a present.
Edit: To date I consider myself to have been pretty lucky. Only real "issue" I ever had was having my bags pawed through because of a bottle of sunscreen... that's how I now know the max size for anything liquid is 3.4oz... my 5.6oz bottle must have been pretty darn scary, what with smelling kind of like banana
LOL
Obviously, 3.4 oz of explosive lotion is not enough to worry about, but, 5.6 oz is enough lotion to take down the whole plane with.
Sometimes I wonder what TF they are thinking when they confiscate someone's nail clippers, as they could be used as a weapon.
If I had my choice of a laptop of a nail clipper to use as a weapon...and I was bringing in onboard to take over the plane with...I don't see going with the nail clipper.
One time I had a device used to take biological air samples I needed for a project I had to fly to....and it looked sort of like a long thick battery tube with a "Statue of Liberty" platform on top where the air samples were drawn into...TK70 more than TK75 sized.
An agent was looking at it like it was from mars, and was experimentally swinging it like a club, literally weighing its potential to be used as such.
I asked him to be careful with it, because it was an expensive scientific instrument that I needed to work when I got to my destination.
He said, I don't think I can let you onboard with this, it could be used as a weapon.
I said "Why would I want to use a $20,000 scientific instrument as a club when I could just get a bat for $10?"
He said "I guess you're right, here you go" and put it back in its case and I was on my way with it.
In the plane, I'm thinking, if I wanted to take down a plane, with a club-like device, would I really have cared if it were expensive, it it worked?
I mean, its not like I'd WANT TO take down a plane, but, logically, if he thought it COULD be used as a club, he should have also realized that a terrorist plot, etc....the cell might have spent MANY thousands on planning and equipment and so forth...and an expensive club that got on the plane would have BEEN a pivotal part of that plot.
It would make MORE sense to say, well, one guy with a club would not be likely to overpower 100 passengers with it, so, its an unlikely plot...
...than to say, yeah, its too expensive to be chosen as a club.
I've also seen them have a guy beep going through the hoop, say he forgot to take off his watch, and hand them the WATCH to scan, and, when it beeped, say, OK, thanks! and give him back the watch.
Maybe its a lack of proper training/basic understanding of the concepts they are supposed to be responsible for.
