Careful use of DCT can fool the machine into accepting a plan. The rules regarding maximum distances on DCTs are different from country to country, and the computer knows them all
Logistically at Deauville, you can't talk to ATC as such - in fact flight plans are filed by Minitel terminal at the foot of the tower. From experience, the best bet is to ask for Direct as you taxi out, and hope for the best. SITET-MID, or even DCT MID does occasionally happen, just as you say.
2D