Twenty colonies suggests a beefarmer who doesn't recognise the risk of putting bees in full view. Proactive action to locate the farmer or beekeeper would help all three parties involved: (1) The beekeeper, who will not only lose the lot, but also an apiary site and the goodwill of the farmer. (2) The farmer, having had thieves on his/her land (and who may return for farm equipment) will probably chuck the beekeeper off that land (and reject future beekeepers). (3) Beekeepers in general, because the more that hives are seen, the more likely it is that thieves see a new and easy target.
Even if access to the field and hives is impossible for thieves in a 4x4, it still puts in their mind the idea of stealing hives, which can be put into action elsewhere.
