The Oct. 6 Maine Marathon and Half Marathon bumped their heads against the 3,500-registrant ceiling when the clock struck midnight on Saturday, Sept. 7. So that’s that. No more entries taken. Simple, right?

Actually no, if you think about it, or if you talk to the race’s co-directors, Howard Spear and Bob Aube. Division of labor between the two — and labor it is to stage an all-volunteer (about 600) race on such a scale — is difficult to sort out, but Spear does handle mail-in entries, and Aube (also the assistant sports editor for the Portland Press Herald and Maine Sunday Telegram) oversees online registration (roughly 85-90 percent of the total). It’s Aube who points out that a banshee can never be built in to wail when the 3,500th applicant emerges, because snail-mail operates in a different dimension, as it were.

So, some wiggle room is necessary in determining registration’s red line, and it was with a handful of spots still open as of Sept. 6 that directors decreed the midnight deadline on Sept. 7.

A further complicating factor is that race sponsors (who receive complimentary entries) and charitable groups who participate tend to miss the deadline. Groups such as the Leukemia Society’s Team in Training, the Maine Army National Guard and the Maine Children’s Cancer Program add as many as 200 entrants to the field, so extra bibs — this in addition to the stated 3,500 — are left available for them.

But just because the entry deadline passes, don’t think people stop trying to get in. Once registration closes, Aube and Spear know they will start getting constant calls and emails, the majority from out-of-staters.

Somebody wants to run with a relative or a friend who’s racing. Somebody else needs to complete the 50-state-marathon string. Somebody wants to come to Maine from far away. Some guy is in hot water because he was supposed to register his wife but forgot.

“We just can’t accommodate everybody,” Aube says. “We don’t like saying no, but we have to.”

Spear notes that the event also draws queries from elites checking to see whether travel, a place to crash, and comp entries are available. But such expenses are not in the budget and would cut into the impressive charitable donations (last year, $60,000 to Strive and several thousand to other causes).

Plus, Spear is probably the wrong guy to cadge a freebie from. More than anyone, he is the tender of the Maine Marathon’s egalitarian beacon, and sees no reason to comp a 2:18 guy but not a 4:18 guy. Or the other way around.

Wait, there’s another complicating factor. Every year, there are people who show up at packet pickup and say that they are registered — but the race has no record of it. A mail-in may have gotten lost in the mail, or an online entry somehow overlooked. (Aube, who has worked many races over the years, notes that this phenomenon occurs at almost all road races, not just the Maine Marathon).

So, these situations need to be figured out.

“We can go online to research it, and sometimes, it’s just ‘sorry, you didn’t register,’ ” Aube said. “If it seems legitimate, we usually try to fit them in. But they still have to pay.”

The 3,500 counts marathon walkers, who can choose to start at 6 a.m., but not relay teams. Last year, 101 teams of two to four runners participated, and about 90 teams are entered this year.

In the half marathon, women entrants usually outnumber men by about 2-1, Aube said, while the marathon is about 60-40 male. Normal race attrition is the numerical safety net: There were a total of 2,968 finishers in 2012.

IF YOU MISSED OUT on the Maine Half, consider the MAINEiacs Charities Half Marathon (and 5K) at 8 a.m. on Sept. 29, in Hampden. The course is a rolling out-and-back. Online registration, at www.runreg.com, is open until midnight Friday, and the entry fee is a throwback $35, or $40 on the day. (Shirts are gone, though.)

John Rolfe of Portland is a road runner. He can be reached at 791-6429 or at:

jrolfe@pressherald.com