I have no problems with the 7.5" pads flying off the 6" backing plate. The design of these pads almost guarantees that the pad will be centered on the 6" plate (which is actually 5-7/8") & this is very important.
Also, the velcro attached to these pads is secured much better than the LC 6" & 6.5" pads so I'm expecting better durability from the 7.5" pads.
Is it possible that the velcro on you backing plate is worn or dirty? Are you using a 6" plate?
I'm new at this so I limited speed to about 4 with any product.
When using the PC, are you placing the pad on the paint, turning it on & working the product, then turn it off before removing it from the surface? If you do this, I don't think the pad can fly off.
I know this 'cause I was using the PC and, when I turned it on nothing happened. I saw the extension cord had separated from the PC's power cord so I put the PC down (pad facing up) and plugged the cords together.
The PC immediately started & the pad flew off like a frisbee. I was luck it missed everything & ended up on the lawn so it went in the pad wash bucket & it's time to mount a new pad.
I'm in Lockport.