It is! Trading your own account in front of a client's order with knowledge of your client's order is, indeed, frontrunning!

However, given domains are not securities and domain registrars are not FINRA members or registered securities broker-dealers, I don't think this is "frontrunning" in the sense that you're used to hearing the word.

So who knows if it's even illegal, and even if it is, who knows what recourse anyone has about it, given how quasi-legal and international the ownership of domains is.

Yes, and it's a well-known practice of scummy registrars like godaddy.

yes, it is. I was thinking taking them to consumer protection court, but I realized it is not worth my time.