I don't think the issues regarding hand luggage have changed that much in recent times. It's just that the security agencies are actually putting in a bit more effort these days.
It's always been up to the security inspectors discretion as to what could be used as a weapon. I've had to transfer expensive specialist tooling from carry on to hold baggage to get onto flights before. It's annoying, but it's got to be less annoying than having some ________ (insert political/religious affiliation) crazy ruining your day.
With Solus I've carried cannister lights around the world to various trade shows etc. Always in hold baggage though. I always put in a brochure or something to identify the light to assure the inspectors that it's not a weapon of mass destruction. Other than a slight inconvenience I've never had any real issues with TSA or any of the other security agencies. Almost every time I arrive home I find a card from the TSA in my luggage stating that my bags have been searched.
I find it reassuring that they do actually bother to check properly. Ten years ago you could have carried just about anything on in hand luggage as long as it didn't look like a gun. Now that they're stopping people from bringing nail scissors and shampoo onto flights it's hardly surprising they weren't happy with the metalsub
(the colour of the paint probably didn't help)
KevJ