Originally Posted by BlueMilk

Time to remeasure your luggage. Excepting the port side of the J cabin, conforming carry-on luggage does fit the CRJ fleet. In fact, it fits easily.

Whether or not one owns a conforming carry-on (and can pack it under the weight limit) probably determines opinions on this policy.

For those worried about it, think of it as an opportunity to buy new luggage. Lot's of good advice on this elsewhere on FT.