I replaced the carpet in my prior Journey. It had one slide in the living area. The installer was able to remove the old carpet from under the slide with the slide extended, and install the new carpet. In our case, the outside edge was covered by the couch, which was attached to the slide.
It would be a good idea to adhere the carpet under the slide with a 1" wide fastener (screw and fender washer) so that when the slide moves in and out it won't catch an edge of the carpet and pull it up.
The challenge is finding someone to do the job for you. Home installers will do the installation like putting carpet in your home. More care needs to be taken in certain areas, such as under the slide.
Never had a problem with it coming up in my prior coach.
'07 Winnebago Journey 34H - CAT C7, Koni's, MCU's, SS Bell Crank, Safe-T-Plus
'07 HHR Toad, SMI AFO, Blue OX