I can recall only one occasion where an older bottle showed signs of seepage but still turned out to be drinkable. Obvious seepage, or signs of sticky residue under the capsule, seems like it's usually a kiss of death. Is there such a thing as seepage that's NOT necessarily a bad thing?
Does it make a difference if it's an 20-year old Bordeaux versus a Port? I've got a few 77 vintage Ports that are showing the signs, and it probably started years ago, before I acquired them.
I even see plenty of bottles in auctions or on retail web sites that are described as showing signs of seepage, yet they are still priced quite high in some cases -- are people actually buying these bottles?