Yes, Colonel Jaques Bouvar, aka SPECTRE #6, erred by opening the car door himself, while dressed as his “widowed” wife. However, a compelling question remains.
Why was he even at the funeral in the first place?
He’s faking his death, presumably to escape 007, who is hot on his heels. Perhaps others as well. So, why not just have his actual wife go to the funeral as she would be expected to, while he stays in hiding elsewhere in the world, while the funeral proceeds?
Because Madame Bouvar is dead.
And she has been dead for some time. My theory canon is that Jacques Bouvar married the wealthy heiress, secretly murdered her, and has been using her identity to access her wealth, social position, and as a means to travel disguised. Her family’s mining business has been providing SPECTRE with money laundering, heavy machinery, and access to African uranium (some of which went to Dr. No’s nuclear reactor). The Corsican section of SPECTRE has been planning the downfall of young Sabine(?) since her debutante ball.
SPECTRE had a female impostor candidate set to take Mme Bouvar’s place full-time, but the cosmetic surgeons and voice coaches were occupied, prepping Francois Derval’s impostor for the Vulcan atomic bomb theft.
Alternate Theory:
Madame Bouvar was kidnapped.
After marriage, the Colonel manipulated her to estrange her from her family, with the same results as above. No. 6 keeps her alive, but captive and out of contact, for possible future ransom.
Basically, if she was still alive and willing, then her husband would have had her go to his faux funeral. Why risk himself to 00 agents on the hunt if he can just have her do it? She’s got to be dead or captive.