DELL Vostro 3550 stacking issue

At work I often order a few laptops at the same time. Because of this it often occurs I install one of the laptops, then put another one on top to install that one. Now I had a Vostro 3550 on my desk and I put another one on top of it. When I turned it on the screen stayed black, or at least so it seemed. After a while I noticed there was a faint graphic showing, so my guess was the backlight was broken. I pushed the power button, pressed F2 to enter BIOS hoping that would help, then when I turned the laptop to the light to see if there was something on the screen it turned on. I put the laptop down again, it turned off. Lift the front up half a centimeter, screen turns on.

So I was thinking, must be a bad connection, right? Well I had another 3550 still in the box, so I removed the top 3550, put it aside, put the other one on there, turned it on, same issue! This was too much coincidence for me and I quickly noticed that the 3550 doesn't have any buttons to detect whether the lid is closed, so it uses magnets to do this. Well of course if you stack two laptops on top there's always a lid nearby, I didn't expect it to be this sensitive though...