Nope, there wasn’t, except that she might have lowered the psi before pouring (unlikely).
You know how you tip a glass to get a good pour of beer? The tube does the same thing, but extra carefully for a growler. The less C02 you lose during the pour (foam) the longer your growler will last.
The only way you’re going to get more than a couple guaranteed days out of a growler is if it’s filled with specialized machinery. If you saw it done at the tap, anything more than that is a gift.
Sidenote: I have started to see double-walled growlers that you can inject your own C02 into! That would let you maintain freshness for a lot longer, not to mention temperature.