It should be no surprise to anyone who has travelled through an airport that there are some common-sense restrictions on what we are allowed to bring along in our carry-on baggage.

Things such as meat cleavers, shotguns, rifles, handguns, live bullets and all manner of butterfly knives, switchblades and, yes, even throwing stars are all items we should leave at home with our far more benign household items.

But do passengers really need to be told to leave these dangerous weapons behind? After Sept. 11, 2001, saw hijackers take down four planes with box-cutters, it should be more than obvious that these objects are a no-no, right? Apparently not.

Through access to information requests, CBC News has obtained a list of items seized or identified as potentially dangerous by the Canadian Air Transport Security Authority (CATSA) at airports across the country from Jan. 1 to Dec. 31, 2015. Here's a look at ten of the most interesting incidents:

The fake grenade

There were many instances of passengers trying to take grenade-looking items through airport security, but in most cases they simply turned out to be lighters. In one instance, however, the grenade turned out to be an inert grenade.

In another incident, a passenger was caught at Toronto Pearson International Airport with a grenade-shaped item that turned out not to be a lighter, but rather a marijuana grinder shaped like the projectile. The device was seized and the passenger was allowed to board the plane.

The spear gun

Officials at Montreal's Pierre Elliott Trudeau International Airport searched a passenger's bag after a scan revealed what appeared to be firearm.

Police and screening personnel discovered the item to be a spear gun, which was then allowed to remain in the passenger's checked bag, and the passenger was cleared to board.

Flares and bullets

Live bullets are one of the most common seizures at airport security, so it's no surprise officials at the Trudeau Airport wanted to search the carry-on luggage of a passenger who appeared to be carrying them.

When police searched the bag they found not only eight live bullets but three flares as well. The items were seized by police and the passenger was cleared to board their flight.

Marijuana

Screening authorities in Montreal also conducted a search of a passenger's bag when an X-ray appeared to show a saw blade concealed within. The search did not turn up a saw blade, but it did reveal a "small" amount of weed.

While it may be illegal to possess marijuana, especially when trying to clear airport security, law enforcement officials simply seized the drug, warned the passenger and then cleared him to board his flight.

Shotgun

Screeners at Vancouver International Airport called in law enforcement when they discovered what appeared to be a shotgun in someone's carry-on luggage.

Sure enough, when the bag was searched, screeners found a 12-gauge shotgun, which had been declared. The problem was that the passenger misunderstood the boarding instructions and, instead of checking the gun with their luggage, they tried to bring it on the plane.

Police escorted the passenger back to where he could check in the gun, and he was then allowed to board the plane.

In another case, screeners at Calgary International Airport found six antique rifles, which were then properly declared and the passenger was allowed to board.

Tear gas

Officials at Pearson ordered a passenger's carry-on luggage to be searched when an X-ray of it appeared to reveal a canister of mace concealed within.

The item turned out to be a container of prohibited tear gas, which was then seized by police. The passenger was allowed to board the plane.

Sword

Screeners in Montreal operating the X-ray machine noticed a passenger was carrying a sword cane in their checked baggage. Police were called and the item was judged to not be a prohibited item so long as it remained in the passenger's checked baggage. The passenger was cleared to board.

Blades

Along with live bullets, it seems as though some of the most popular items to try to sneak through airport security are blades. There were countless incident reports for people carrying throwing knives, ninja throwing stars, switchblades, meat cleavers and kitchen knives.

In almost all cases, the blades were confiscated by security officials and the passenger was then allowed to board their flight.

Pellet gun

Security screeners at Calgary International Airport called in law enforcement when they discovered a passenger appeared to be transporting a gun in their carry-on luggage.

When the bag was searched, it turned out to be a pellet gun. The weapon was seized by police and the passenger was allowed to board their flight.

Taser

Screeners at Winnipeg James Armstrong Richardson International Airport stopped a pilot from boarding a plane he was scheduled to fly when they discovered a suspicious item in his bag.

The item was removed from the bag and appeared to be nothing more than a flashlight. A screener even managed to turn on the light. But a more senior official, familiar with the way a Taser could be hidden in this device, stepped in and revealed its true purpose.

Police confiscated the Taser and, after answering a few questions, the pilot was allowed to resume his duties.