Tandems take up a miniscule percentage of bikes stolen . . . as there are a heck of a lot less tandems than singles!
Having said that, in our 32+ years of tandeming we personally know of 2 tandems being stolen.
One was locked in a shed and a full custom Andy Gilmour (Tucson, AZ) tandem with the latest componentry, custom red anodized cranks, seatposts. Something that would be difficult to sell in the local marketplace. Thief obviously knew what they were after and the value of the machine. Speculate it ended up being sold out of state somehwere. Never was found.
The other was parked in front of an eatery in the small town of Benson, AZ (unlocked). Owners came out, tandem had vanished! Insurance paid for new tandem. However the stolen tandem (another custom one) was found in the nearby desert 6 months later. The only thing missing was the computer! Speculation was that some kids took it for a joyride and then dumped it.
If we leave our tandem unattended/out of sight when we are out, we always put a lock on it. It's not a guarantee of it not being stolen, but certainly serves as a deterrent.
Today we cycled out to a small town in Idaho to see parade and attended festivities in a local park. Parked the tandem next to a fence, looped cable/lock through fence/back wheel/rear triangle and had fun.
Yup, tandem was still there when we got back!
Like wearing a helmet, a lock is cheap insurance!
Pedal on TWOgether!
Rudy and Kay/zonatandem