I think the oft-cited solution to this if you're flying domestically in the US is to pack a flare gun, declare it, and use a non-TSA lock on the suitcase. Appar

I think the oft-cited solution to this if you're flying domestically in the US is to pack a flare gun, declare it, and use a non-TSA lock on the suitcase. Apparently, this also greatly reduces the chance of your checked baggage getting lost or misrouted.