I always wonder when I see this stuff on markets/car boots, that also goes for hanging baskets, planters and garden ornaments, the 'used stuff' papers are also worth a look. This sort of crime isn't worth the police time that it would take to recover your goods, but well worth you putting in a little of your time. Also it's very easy and cheap to security mark at risk portable items, including childrens cycles etc.
Good luck.