Hello Qatavin,
Glad you like the mod, it was a must have mod for me as well, therefore the maintenance fork happened - that's how I got into Factorio modding in the first place :)
I think something like this could be possible (just off the top of my head, thinking how the stop sign does something similar already). But first of all - what would be your particular use-case/scenario? Placing the sign at base exit or something similar?
Best regards,
Branko