Actually, the historical performance of Athens General Exchange Index confirms this rule.

FORBES: Four Flavorful Tastes Of Greece To Ride The Rebound

Historical rows are already the exception, not the rule.

ECONOMIST: Europe.view

But I would propose an exemption to the a promise is a promise rule, and that's the immortal-genius-a-person-of-historical-importance exemption, very much akin to your put-it-away-for-a-generation.

NPR: Family Pauses over Woman's Posthumous Request