Such a nice offer!!!
IIRC, US made seats do not meet the safety requirements of most foreign companies (their safety requirements are typically stricter). But foreign seats exceed US requirements which is why their seats can be used here (for the most part).
this is only what I recall, so I'm def not saying its the end all be all.
Actually, you can't use foreign seats in the US either. It's because each country has its own laws with rules around what the seat must pass. Seats are only tested and labeled for the rules in the country in which they are sold.
There can be nuances to the way things are tested too. For example, Canada requires a tether, so all seats are tested using tethers. In the US, they are tested without tethers. The tether reduces the head excursion, so there have been times when seats rated to 40 lbs in the US were rated to 48 in Canada.
I think this has changed, but years ago, Canada defined a "child" as someone under 48 lbs. Therefore, a "child restraint" could only be rated to 48 lbs. So, seats like the Britax Marathon that were rated to 65 lbs in the US, could only be rated to 48 in Canada.
Some foreign countries require anti-rebound capabilities in rear facing seats which makes their rear facing seats superior, but the same country may max out harness weights around 40 lbs (it's in kg) which makes the US seats with high weight limits superior.
In the end, all countries have different requirements and by using a foreign seat, you're using one that wasn't tested to your country's requirements. Does that make them unsafe in another country? Nope. Physics don't change when you cross the border and I've known many people who have used imported seats for a variety of reasons.
