Is it believable that 40 to 50 people a week actually are accidentally bringing guns on commercial airline flights each week?

From the Orlando Sentinel:

"It strains credibility when 40 to 50 people a week show up with guns at the security checkpoint and then say 'I forgot.' They didn't forget their ticket. They didn't forget their pants. They've been on notice for over 12 years that guns are not permitted and it's time they be held responsible for violating the law." . . .

To put this in some perspective, 16 million passengers travelled per week in 2012.  40 or 50 cases out of that is about 0.0003 percent.  But it probably makes sense to say that 16 million is not the right group making the mistake here.  Suppose we are dealing with the 5 percent of adults who carry permitted concealed handguns (putting aside non permit holders and that permit holders are relatively wealthier and are therefore more likely to be flyers).   That would then be 800,000 (16 million times 5 percent).  Then implies an error rate of between 0.005 and 0.00625 percent, or about 5 or 6 per 100,000 travelers.