Transporting booster seat by air

I am travelling via Air Canada within Canada in the next week.

I would like to transport my two CLEK booster seats for my daughters to use in cars and taxis when I reach British Columbia. The dimensions of the CLEK are small (5" X 16" X 14.5"). This seems to exceed the "one personal article" by 1.4 inches, but fits the "one standard article" size (so we know they will fit in the compartments). http://www.aircanada.com/en/travelinfo/airport/baggage/carry-on.html

We don't want to check the booster seats (for impact prevention) and we don't want to check our clothing - we're travelling for just 4 days, and have a tight transfer in Vancouver, so we'd like to just bring carry-ons and not bother with checked luggage at all. I was planning to pack the 4 days of clothes in the girl's school backpacks - which again fit the "standard item" measurements but not the "personal item" measurements.

Does anyone know what will happen at check-in if we try to bring the seats? If our seats are an inch too big, will they confiscate them or boot us from the flight? Or send us back to check either the seats or our clothes? Will they even measure them at all?

What would you guys do? Pack less clothes (basically one purse's worth for each kid) or pack their backpacks and hope the seats get on? Do they sit there with a measuring tape for every carry-on?

(Yes I know I can't use the seats on the plane. I've considered the options and am okay with just seatbelts for the girls, they are very long and tall - I've moved on to keeping them safe and legal once we're on the ground again in BC.)

Thanks for any suggestions - good news or bad!
Kat

Chances are that AC won't hassle you on the issue--but just incase, be prepared to gate check two of your backpacks in order to carry the seats on to the plane...so put everything you'll need while on the plane in one primary carry-on. The Clek does fit in the footspace under seats, so they shouldn't hassle you about the size.

-Nicole.

I agree with Nicole re. be prepared to gate-check the backpacks so you can bring the boosters on board.

Alternatively, get everyone a rolling carry-on suitcase (std size) and put the boosters in two suitcases, and the rest of clothings and essentials in those as well. Pack the backpacks with less (only things that they need on the plane), so it would be squished down as their personal size carry-on.

As for how they determine what carry-on would be allowed... There is a metal frame of the personal and standard size carry-on. If there is an issue, you would be ask to insert your carry-on into this measuring frame. If it fits, then you are okay to bring it on board. If it does not fit the frame, then no-go.