I know this is slightly off-topic, but for lack of a better forum, here goes:
I noticed on the NW web site that they limit carry-on baggage to one piece. I have flown at least 15 segments over the past 6 months with 2 pieces in the cabin (mainly on 747-200s & A319s) and not a word was said about having 2 bags. I carry a backpack for stowage under the seat and a small rolling suitcase for the overhead bin. Has anyone else experienced limitations on carry-ons recently? In contrast, I see UA's website says they officially alow 2 pieces in the cabin.
Thanks in advance....

Aloha