I've done dozens of quilts with spray basting and it didn't gum up my machine. If your service person believes this, it may be a bias on his part because he doesn't understand spray basting, by the time you start to stitch, the glue is dry..not gummy. If you sprayed too close to your machine and got the spray glue inside your machine, then, maybe..but that's still not the fault of the spray glue.