I was complaining about some of this to the other Ambassadors the other day. My teams seem to show up, but other things are random at best. Just as one example, I order stuff off of Amazon frequently, and I get get the "Tracking" card for those. However, in the past couple of weeks, I've ordered two things from the Play Store (a Nexus 7 and a Chromecast) both of which shipped separately. I got the tracking notices in my gmail, but never got the cards.
The inconsistency is a bit concerning. I have trust issues with it because what if it decides to not tell me about a delayed flight or traffic? So far it's been ok there, but if I can't trust it to give me shipping notices/tracking, can I trust that it's always going to pick up on a flight or hotel reservation? I really wish they'd add a manual "Create a Google Now Card" to it so I could manually add a flight or hotel or tracking number....etc.
But no, I haven't had team problems yet.