If you get an invitation without a response card but with a Simchas Chassan ViKallah, it seems plain to me that nobody expects you to drive an hour or more just for the chuppah, then drive back home and turn around and then come right back for the 10:30 PM simchas chassan viKallah.
In this case, it’s obviously an either-or (but if you want to come to both then obviously they’ll be just as happy).
BTW, I happen to feel that this should be the norm; only very close family and select close friends should receive a response card. This would eliminate the “second class” issue.
The norm would be that unless you’re, say, either a brother or you’ve learned with the guy for 20 years, you’re getting a Chuppah and Simchas Chassan ViKallah invite. This would save millions of Jewish hard-earned dollars per year on full invites while still conveying to the invited party that you want to see them at your simcha and would be happy to provide dessert and tea, too, and allow that many more people to be misameach chassan vikallah (and stay for Sheva Brachos, too, once you’re coming that late…)
I am not at all insulted when I get a Chuppah/SImchas Chassan ViKalah invite. I take it as an acknowledgement that they wish me to participate in their simcha to the extent that they can reasonably offer, and I appreciate that. I don’t see the need to be insulted…