I have done the carnet route several times. In each case it was when we were taking a whole bunch of stuff to gigs we had in the UK. Sort of a PIA in terms of paper-work and getting stuff stamped by customs on both sides. Think of it as a passport for your equipment. I guess, in theory, it is supposed to prevent you from taking your gear into a high-tax (VAT) country and selling the stuff there without paying the import duty and VAT, and vice-versa, to keep you from buying some high ticket piece of gear outside the US and bring it back without paying the import duty here in the US. To be honest with you, it got to be such a hassle to schlep our gear that on subsequent gigs we just ended up renting what we needed in the UK. I would think that if you kept the gear to a minimum and just looked like a tourist with a few expensive toys, you would probably be OK. (But, I would still have copies of the purchase receipts.) OTOH, if you are going with cases of stuff and look like you are some big production company, then you might want the carnet. The other thing you also have to consider is what you will say to the immigration officer when he asks you about the purpose of your visit. If you tell him, "work" then you may have some additional issues ... because technically you are not entitled to "work" unless you have the appropriate visa or work permit. I remember the first time we went to London with a camera guy, sound guy, associate producer and the talent. We all went through immigration together and I stupidly said that we were from LA to film some segments for American TV. WRONG ANSWER. As Ricky said to Lucy, "... you got a whole lot of 'splainin' to do ..." Somehow I was able to talk my way out of it ... but it is a lesson I never forgot.
Scarlet X # 1859 “Bettie Page”
“… preparing to ‘whip’ the competition …”