As has been said here before stickers, like relicing or signatures are just variations in the finish of a bass. No different than a paint job or whatever. If the look and "mojo" does it for you then why not? Of course some of the practical aspects have been pointed out like fading and peeling. And this paint-sticker connection can be noticed in Flea's bass which is apparently a paint job imitating stickers.
And while I'll admit that any bass finish is an artistic creation that must stand or fall on it's own and the skill of the artist, I personally have a personal philosophy when it comes to reliced/ roadworn basses, basses signed all over, and basses with stickers. And that philosophy is that in each of these cases this form of decoration is best when it tells a true story. It's so much cooler in my view if YOU put the wear on the bass or YOU personally met and had each artist sign the instrument so that each signature has a story of who when and where. I'd want my stickers to likewise be there to tell some kind of story, you know, the way people used to do with steamer trunks covered with all the places it had been. Only it's a modern age and you now can cover a bass with stickers of all the places your MIND has been. Dig? But to me, while I'm sure basses with lithographed signatures or stickers all over it have a place, it's no where near the mojo of a similar looking bass that has actually paid its dues!