Depends on where you do the swiping and what you are swiping it to.
Loading a BB card at the cashier with a Staples VGC is not restricted, so you can do $200 swipes. I only do one at a time so I cannot tell you if there is a limit to number of loads at a single visit, maybe someone else can.
OTOH, using MC or CS will limit your load to $99/swipe.

Have no idea why you get an occasional $100 to go through, but given the giltchiness (sic) of WM, it doesn't surprise me.