On the island of Saba in the Caribbean people will list an event to start at 11:15 but if you are familiar with Saban time you know it doesn't start until 1:30
Non saban: hey I thought you said the party started at 5
Phrase: To be notoriously late, with the intentions of being punctual.
When one has achieved the level of consistent tardiness to the degree that one's friends, family, and co-workers automatically add an additional 3 plus hours (up to several days) to any stated arrival time, therefore not to be frustrated by the lack of punctuality.
Brian, "Where's Tina with that side dish she promised to make?"
Alex, "She's probably on ShannonTime."
Brian, "So tomorrow then? Cool."