Here is the answer from Scrabble Club in Thessaloniki:
Αθανασία καλησπέρα,
Αυτοί οι όροι αποδοχής που βλέπεις στις ιστοσελίδες όλων των ομίλων είναι πραγματικά οι όροι αποδοχής του Ελληνικού Αγωνιστικού Σκραμπλ.
Είναι δηλαδή αποδεκτές όλες οι λέξεις - λήμματα, που υπάρχουν στα δύο λεξικά (Τριανταφυλλίδη και Μπαμπινιώτη), σε μια προσπάθεια οριοθέτησης
του αγωνιστικού σκραμπλ. Βέβαια οι κανονισμοί και ο όροι αποδοχής επεξεργάζονται ήδη και είναι υπό αναμόρφωση. Ότι χρειαστείς, είμαι στη διάθεσή σου
Δήμητρα Τζάρα (Η πρόεδρος του Ομίλου Σκραμπλ Θεσ/νικης)
Translation:
Good afternoon Athanasia,
these terms of acceptance you see on the websites of all groups are actually the terms of acceptance of the Greek Competition Scrabble.
More specifically all the words - entries that exist in both dictionaries (Triantafyllidi and Babiniotis) are acceptable, in a bounding effort of
the Competition Scrabble. Certainly the regulations and the terms of acceptance are already under process and revision. Whatever you need, I am at your disposal.
Dimitra Tzara (The Chairman of the Group Scrabble Thes / niki)
From this answer I get the meaning that really the terms of acceptance differ from the board game and the Tournaments-Competition Scrabble.Since the game you have constructed has options for time or tiles' colour etc as you and Scotty said, it is possible to put foreign words in a separate category which you can activate, if you want to play accordingly to the official tournament rules, and disable if you won't do that.I know that this means a lot of work but don't bother for it.Give me instuctions and all effort will be done from me.If I see in the meanwhile that I can't manage it I 'll refer that to you and we will forget about this issue.The only thing that you will have to do with later, will be to put the option into the game. Whatever you think and you decide