Hi Pal I am a full time mole catcher the reason your traps are probably been trigger is that you have not done something right,
No 1 make sure there is nothing foreign in the run ie, grass,roots loose soil
No 2 smooth the bottom of the run
No 3 make sure the trap doesn't move and make sure the bottom of the kill loop is pushed onto the soil a bit
No 4 try not to get any loose soil in the run once the trap has been placed,if you have gaps at either end then make sausages out of soil from the mole hill and try and put these around the trap to stop the soil falling under the trap,and cover t