Yes, I have seen other discussions about getting into line in an Orthodox Church for Communion, but stop and think of the word: Com-Union, or union with. Are the churches involved united in faith, the Orthodox faith? If your church is not in union with the one you are visiting, then your reception of Christ's Body and Blood condemns you.
Maybe there is no canon law specifically about cross-communion, but how about the priest's ordination? Consider what is said and done in this quote from the goarch.org website, liturgical texts for the ordination of a priest:
After the consecration of the Eucharist, the bishop places the body of Christ into the new priest's hands with the following admonition:
Bishop: "Receive this Divine Trust, and guard it until the Second Coming of our Lord Jesus Christ, at which time He will demand It from you."
In the Antiochian liturgical text, found in the Hapgood liturgicon, the admonition by the bishop is a bit different, and a bit more stern:
"Receive thou this pledge, and preserve it whole and unharmed until thy last breath, because thou shalt be held to an accounting therefore in the second and terrible Coming of our great Lord, God, and Saviour, Jesus Christ."
It is the priest's most sacred and basic duty to preserve the Body and Blood of Jesus, until He returns. Were I a priest or deacon, I would be VERY careful about communing anyone I wasn't sure of. Yes, yes, there have been discussions for years about allowing Catholics and Orthodox into each other's Communion lines. I have had arguments with prominent members of the Parish Council in a previous hometown, since we had Melkites and Maronites and Syriacs in town. Talk about total confusion!
It seems to be a falsehood to commune someone with whom we are not in total union.
Just sayin', I could be wrong.