Funny you mentioned embargoes. This is from the TOS for their latest endeavor.
https://b.tc/conference/2024/bitcoin-is-a-record-competition-tos
“NON-EMBARGOED SANCTIONED RESIDENCY
You warrant that you are not a resident of any country embargoed or sanctioned by the United States including but not limited to: Cuba, Iran, North Korea, Sudan, Syria, The Balkans, Belarus, Burma/Myanmar, Burundi, Central African Republic, Democratic Republic of the Congo, Iraq, Lebanon, Libya, Mali, Nicaragua, Somalia, Ukraine/Russia, Venezuela, Yemen or Zimbabwe.”