If you don't salt and someone slips they can sue.
If you do salt and someone still slips they can still sue, but you have a defence that you tried to make it safe.
The chances of someone slipping are a lot less if you did put salt down though,.. so its a no-brainer for me. I've used a huge amount of salt this week, but at least I could still work & I got all my jobs completed before the hols!