HARRISBURG, Pa. (WHTM) — The short answer is the same one we’ve been hearing for 22 years (ever since Real ID requirements were announced), even if the effective date has slipped multiple times: Yes, you do need a state-issued Real ID or other acceptable form of national identification to be nearly certain* you won’t have trouble getting through a TSA checkpoint beginning Wednesday.

But see that asterisk? The longer version of the story is: The opposite of that statement is not exactly true. Just because you need Real ID (or a passport, military ID, Global Entry card and so forth) to be almost certain you won’t have trouble, doesn’t mean you’ll definitely be left off the plane if you don’t have the proper ID. The reason? The same reason why you would eventually get home if you lost your driver’s license while on vacation, even before the Real ID requirement.

“If your ID is expired, or if you lose it on a trip or something like that, there’s a procedure to go through identification purposes and additional screening to get you where you need to go,” Harrisburg International Airport spokesman Scott Miller said. “That process has been in place forever.”

Dating back to… well, dating back to the point of all this, TSA spokesperson Lisa Farbstein reminds any of us who are cranky — however understandably so, in some cases — about the changes.

“Not one of those terrorists had an authentic, form of identification,” Farbstein said of the 19 men who hijacked airplanes on Sept. 11, 2001, and crashed them, killing everyone on board and thousands of people on the ground. “Every one had fraudulent ID, and so Real ID was born out of the ashes of 9/11.”

One piece of good news? “Wednesday tends to be a little lighter in terms of the travel volume through our checkpoints,” Farbstein said.

Beyond that, Miller said, Wednesday morning at Harrisburg features nothing but American, Delta and United flights disproportionately carrying midweek business travelers, who tend to travel a lot and know the rules. The first flight on Allegiant — a more leisure travel-oriented airline carrying less frequent travelers — is later in the day. Frontier, which tends to serve broadly similar travelers, doesn’t have any flights scheduled Wednesday.

On the other hand, fully 40 percent of people who fly from Harrisburg leave before 7 a.m., so the system will be tested Wednesday morning.

Farbstein and Miller both suggested leaving a lot of extra time if you’re not sure you have the right ID and a little extra time if you are sure, just in case you’re in line behind someone who doesn’t, although plans are in place to pull those people aside to allow properly-credentialed passengers to pass through as quickly as possible.

The reason for a lot of extra time — as in, hours extra — if you might not have what you need? Because you could be in more company (although no one is sure how much more company) than that occasional person who loses a license.

“How long will it take depends on how many people are here who aren’t prepared,” Miller said. “Instead of one person a week, it might be fifty, a hundred — we don’t know. That’s the difference, and no one knows that yet.”