Of course not, real cavers use a bobbin.
A common concern among cavers is what can go in a carry on bag when flying. My thought is, if it is expensive or if not having it immediately will prevent me from caving, then I’ll try to bring it in my carry on.
The TSA has an official Facebook page called Ask TSA where you ask if an item is allowed in your carry on.
After dozens of flights, domestic and international, I haven’t had an issue bringing caving gear with me. Rotary hammer, batteries, bolts, >50 steel Maillons, bobbins, wrenches, rope, helmet, carbide headlamp, and 5 lbs of Sulphorhodamine B dye have all gone in my carry on. If it is metal, not sharp and less than 7” (17.75cm) long, it probably is allowed in a carry on. Don’t even try to bring your El Cap rack.
What I’ve learned works well is being overly nice (But not fake. It’s a relatively thankless job.) and telling the TSA that you have some strange items before your bag gets scanned. Organize your carry on so like items are together, in their own pouch, and they can be quickly removed. Each pouch gets sent through the scanner in its own bin. Home Depot sells these pouches, they work great for organizing your bolts, screws and hangers. Make it easy for the TSA to inspect everything.
Chances are that you bags will still get swabbed and looked at in secondary inspection. If they ask what X is, give more than a one word answer. They usually ask where I’m going rock climbing. This is a good time to strike up a quick conversation about caving and the exciting project that you are traveling to.
Be nice, stroke an ego or two, do what it takes. In the end, the goal is to get everything through security, and remember you have little or no recourse if they decide to not allow an item in your bag.
Safe travels!