Any good remy hair extension will not have their track glued. Weaves should not be sewn through the track, rather around the track. You should not cut the tracks when you come to the end of the row, rather fold the track over and continue sewing in on the next row down. This method is mainly for 'good' hair.
When one gets a stellar set of hair extensions, they would like to potentially reuse them, maybe years later. It is to keep these extensions in good condition for reuse that a pro weaver should always minimize cutting to only extreme (above forehead for example) situations, and never sew through the track. This is the secret of how good stylists keep their customers coming back.
Because they charge more for a reinstall anyway, and their customers are saving money from having to buy as much hair as they normally would. Good hair extensions look better the longer it is conditioned and used.