Hey, love your avatar!
The caribou could care less if there is a drill rig out on the tundra, they walk around the existing installations all the time. So do the bears and all the other wildlife.
Not to hijack the thread here, but this would be a good lounge topic. I could go on for a while...

Back to the baby seats, I have three seats (one's a booster seat that we haven't started using yet) I'll try putting all three in the back of the X and see how they fit and report back tomorrow.