Why no one likes to explain propagation

We (Stem) signed up with a new hosting company today, Fused Network. Well, kinda new since Slaw has also hosted there in recent years. Needless to say, I wouldn't have signed on for the second account without a great experience on the first. That said, what I'm appreciating at the moment is the humour embedded into the sign-on experience. This is a quote from their welcome email:

"Please keep in mind that your domain name will not be visible on the internet for between 24 and 72 hours due to DNS (Generally they're up within 15 minutes though). This process is called Propagation."

Any time you start up with a new web host, or make a change to domain name settings, the companies involved need to pre-explain the answer to the next logical question: "how long until my website works?".

Unfortunately, it's a question that has no answer. It's pure guesswork. I have seen propagation happen in 30 seconds - literally re-setting name servers, hit refresh, boom it's up. I've also seen it happen in 24 hours (more for country-code domains like .ca's), 4-6 hours, and the more common time frame offered by Fused, under 15 minutes.

Perhaps I'm the only one, but I get the giggles when someone tries to explain propagation to me. I love the '24 to 48 hours' part; or even better, Fused's ultra-safe "24 and 72 hours". 72 hours! wow, that's long .... yes... but... it could also take 30 seconds. :)

Somewhere between safe and sorry, the answer should be 'we have no clue'. It's too bad no one likes that answer. Even when it's the truth.