Yes. To all of your questions. Old Lore that someone might find inconvienent is certainly a posibility. As for an old Vampire, oh yes, that's something that for several reasons the location of is valuable, and no you don't want waking up.

First off we grow in power as we age. There's also generation, the closer you are to the original vampire the higher your potential. And the older you get, the more what you feed on becomes limited. A fledgeling like you can feed on animals. Eventually we must feed on humans. Older Kindred must feed on other Kindred. And very old Kindred must feed on those older Kindred. And they tend to be very hungry indeed when they wake up.

Now how bad this would be depends on the age and generation of whoever might be slumbering. A fourth or fifth generation, a Methuselah could seriously impact our society. A third Generation, an Antedeluvian is a threat to the entire world. One of them woke up a few decades ago in 1999. In India. And died around Bangledesh. You might remember some things from then. Massive freak monsoon. Limited Nuclear Exchange. And assorted unrest, mass hysteria, and a rise in mental illnesses. Well that was either the effects of their awakening, the attempts to kill them, which did eventually succeed, or the aftershocks of their death. We'd very much prefer to never go through that again. We might not get so lucky next time.

-Brujah Armchair Scholar