True, but. . . I have not had trouble with this using the perforated release film from CST. I guess it is because it is easier to get it layed flat if sufficient excess resin is being drawn out. And like you said, too much resin can cause issues, like puddling and wrinkling. I usualy start with just an inch or two of vacuum to hold stuff in place while smoothing out the stuff in the bag.

Earlier on, I had tried unperforated painters dropcloth. Lets just say it was very educational.