I'm not even sure at this point which stickers we're talking about... With ludlows, there have been some fakes, so maybe grading a lower condition sticker makes sense just to verify authenticity... And, then there's protection as a consideration - I am considering submitting my mid-grade die-cuts even though they might get 6's because I think they are less likely to pop perfs if encapsulated.
I believe we're still focusing on Leslie's Series 16 set on eBay. As to verification of authenticity, I'd not trust PSA to accurately do that with Wackys, anyway. Remember, they are not called PNSA. Slabbing die-cuts to help preserve their physical integrity makes sense, really...but you could buy your own slabs/holders and save the PSA expense, yes?
Just to add my two cents on the overall PSA thing: I don't see me ever using them for my keepers, but I have of late bought some PSA 7 and higher graded Wackys as upgrades, mostly because I feel comfortable that when I crack it out, it'll really be a good upgrade. Even if I WAS a PSA guy, I wouldn't send Leslie's 16s in; not high enough quality, IMO.