One good thing about a tag is that you pretty-much don't need to worry about being over your weight limits. The less-good thing is that because the tag takes up space, you have less basement space to carry "stuff" there.
Golden-HVAC is right: You're more likely to not fit into a campsite because of your length, not your width (some exceptions, of course). Our coach is functional with any/all slides in, so it's never been an issue.
Unlike Dennis' fancy Executive, the tag on our 42' Phaeton isn't liftable.