Good point. Before trying anything big, we'll need to store some food and have as much information as possible.

[So a series of micro tests to begin with. Hm.]

They probably won't be too worried if it's just one or two people messing around. For the people who have some kind of powers, tests could be masked as training and target practice in an area that won't hurt anybody. Plus, regular curiousity can explain a little tinkering from just about anyone.