They should have left them there, seven plants in a marsh are obviously not organised commercial activity but someones personal crop that surely takes cash away from the drugs gangs, if someone want to grow their own I say let them do it, they'll only buy it otherwise and feed the problem and more likely to get skunk types that are causing so much more problem than the old school weed that used to be around.
And yes I used to love a bit of old school weed before you ask, not a hint of interest in the stuff about nowadays.