Spray paint X on the BT duct cover?

Hi,
Just wondering if anyone knows why there would be an X spray painted on a BT duct cover which is outside my house?
Checked CCTV can see someone in a high vis jacket yesterday spray paint an X over it, then today somone in an unbranded van pulled up and opened it and took a look in?

I've had a survey done previously for fiber but they wanted 8k for install. just wondering what this could be?

Thanks!

Only time I�ve seen it is when a joint box cover has partially collapsed and is waiting for a replacement frame and cover.

But it could be anything really. Anyone from Openreach could have put in the notes �joint box cover sprayed with grey paint� to help a colleague or contractor find it for any purpose.