Fuji - one reason cross-fixing with a couple of VORs is now included in the PPL syllabus is to ensure that a pilot has something else up his sleeve if visual separation from the ground ensues. Did make note of your use of the word 'might' though, merely opinionating.
Not making excuses because of course not everyone has the luxury of one - let alone two - radio navigation aids and it can be disorientating above banks and banks of cloud, but just suggesting that a well prepared pilot should never be in a position where they are adamantly unsure of their position... it's hard for London to confirm who they are looking at when you pass your mayday without at least an approximate position!
Either way, it's always worth recalling that handy reminder to us all that "Landings are compulsory, takeoffs are not," and I'm in full agreement with FujiFlyer that there are only so many ways 'in sight of the surface' can be interpreted. Low level fog? Apply the relevant IMC limitations that are going to affect you in the immediate, i.e. said fog.
Cheers, Jack.