But there are definitely some without magnets that you can use with the Droid. IIRC Fortte makes some. There are others as well, just can't recall them all off the top of my head. You might want to peruse/search this subforum.
I am using a case with magnetic catch with no problems.
Make sure the magnet is in the flap not the case.
Alsways put the Droid in the cas face out and usb connector down. The docking magnet is in line with the usb connector about .25 from the edge.