Nearly 11 million Canadians have an Air Miles card, but many of them may not be aware of how those miles are collected.

"Sobeys states on their receipts: one reward mile for every $20. However, this is not true," Dartmouth, N.S., resident Keith Kerr wrote in an email to CBC.

Kerr was upset because he'd purchased groceries totalling $80.68 before tax. On its website, Sobeys says collectors earn one Air Mile per $20 spent.

He received only three Air Miles but felt he was entitled to four.

The Sobeys site prominently features the promise that customers get one Air Mile per $20 spent. The asterisk leads to fine print with a list of excluded products. (CBC)

"My question: what does one reward mile for $20 mean?" he asked. He said he's not concerned about the single Air Mile, but rather the principle.

When Kerr complained, he was told he didn't get the fourth Air Mile because he purchased milk, which cost $3.39.

A Sobeys representative told him "regulations in regards to promoting" certain items meant milk didn't count toward his Air Miles.

Other such products include taxes, lottery, tobacco, bottle deposit, fluid dairy, pharmacy, purchase of gift cards and any other non-discountable item. That rule is noted in the fine print of the Sobeys Air Miles site.

It also notes that collectors earn one Air Mile for every $20 spent cumulatively in a Sunday-to-Saturday week, meaning Kerr would get the fourth Air Mile if he spends the necessary amount of money during another stop.

Different company, different reward

How Air Miles are rewarded varies from business to business. At Irving, collectors get one Air Mile for every 20 litres of gas bought. In an Irving store, they get one Air Mile for every $20 in purchases, with many of the same exclusions as Sobeys.

However, unlike Sobeys, Irving counts milk purchases and taxes toward Air Miles.

Sobeys doesn't award Air Miles for certain purchases, including milk. (Andrew Vaughan/Canadian Press)

The only way for collectors to know how their points are awarded at a particular store is to go to that store's website and read the fine print on its Air Miles policy.

Air Miles says more than 220 companies offer Air Mile rewards. While many offer one mile for $20, others do not. Best Western and Booking.com and Expedia offer one for $35, while some hotels like Crowne Plaza and Holiday Inn have the best offer at one Air Mile for every $5 spent.

At the Nova Scotia Liquor Commission, shoppers earn an Air Mile for every $30 accumulated monthly. It also lists exclusions, including taxes, bottle deposits and gift cards. Staples offers one Air Mile for every $40 spent.

A spokesperson for LoyaltyOne, the company that owns and operates Air Miles, told CBC each partnership they reach is different. "However, we work closely with our partners to determine the best earn rate for their business, ensuring collectors are able to get the best possible experience out of the program."

Booking a flight? Prepare for extra charges

Those who collect so-called Dream Miles for travel should also read the fine print, which says restrictions apply and quantities may be limited.

It says collectors must pay taxes, fuel surcharges and other applicable charges and fees on air, hotel and car rental rewards, adding travel rewards may be subject to a minimum advance booking and availability from participating suppliers.

It also says Air Miles terms and conditions apply. The three pages of very fine print include a line that says, "We may change ... any aspect of the program ... without notice and even though the changes may affect the value of miles already accumulated."

In the Sobeys fine print, it says all rewards offered are subject to the terms and conditions of the Air Miles program and "are subject to change and may be withdrawn without notice."