Securing a bike trailer My wife and I just purchased bikes for ourselves and a CoPilot Model A trailer for our 2-year-old.  We can lock up our bikes fairly easily, but the trailer leaves us a bit lost.  Everything on the trailer is easily detachable, and there's no evident way to lock the frame without removing the cover.

Is there an easy way to lock it up?  Currently, we bring it into the house when we're home, but that doesn't help when we bike to somewhere and need to secure it.
It depends a bit on what type of theft you want to prevent.

If you want to prevent opportunistic theft, then all that is needed is to put a lock through the wheels, as a thief would then decide that the trouble of breaking them isn't worth his effort.

If you want to prevent deliberate theft, then adding a clamp to the towbar and locking it with that to something fixed might work, although no lock can withstand a determined thief.

Here is a list of locks, with scores for how good they withstood some tests :
http://www.stichtingart.nl/sloten_resultaat.asp

Although the site is in Dutch, I think you can use it.