Visible crew/equipment: When the chairs are flying through the air in the courtroom, if you look closely, you can see the string pulling one of them. (00:34:30)
Visible crew/equipment: When they're yelling at the pink slime, one of them places a toaster next to the slime. A big lighting screen gets reflected on the metal structure. (00:40:40)
Visible crew/equipment: Vigo just knocked down the heroes who are looking at him powerless. Vigo then makes a gesture and parts the crates behind which Peter hid Oscar. As he does that gesture you can spot in the background on the left (mostly in the darkness) someone's arm doing the same (the movement is not exactly the same so it's not a mirror). (01:34:35)
Suggested correction: This would need more clarification. I couldn't see any string in the mentioned sequences - and for the record, I don't think strings were used, you can easily find interviews with the production team that mention the different trick at work here (they quite literally 'shot' the chairs up in the air).
Sammo ★