Why lock only the front wheel along with the frame?

I bought a Ultra Bike Club Junior bike lock the other day, and it says to lock the front wheel along with the frame. Why only the front wheel... is it because it's more easily stolen? Can the back wheel get stolen too if it's not locked up?

The back wheel is more unlikely to get stolen, according to experience. Probably because the chain can make it a bit messier. There are also lots of bikes with quick releases on the front but bolted wheels in the back. Personally, I try to never leave my bike locked up where I can't observe it, like through a restaurant window. When our group is riding and stops, we lock up all the wheels and the frames.

HTH

If you think that your bike has a chance of getting stolen, buy another lock so that you can lock both tires. Maybe even buy a locking seat post clamp. Bike thieves will take what ever is accessible.

Happy riding

You should lock both wheels and the frame. And if you have a quick-release seatpost, you should consider locking that, too. Locking only one wheel and/or the frame is only sufficient for a short while and if you will be nearby and occasionally checking on it.