There are commercially available bushings for this. Some simply have a slot for the cable, and some also have a roller of some sort at the top of the groove to provide a gentle profile for the cable to follow at the entry/exit to the bushing (usually the cable is held back at an angle with a snatch block, and this CAN lead to wear at the top of the bushing- I know of a job where the cable snapped at this point and 2-3 weeks fishing followed to retrieve the tools and cable)
I have a attached a couple of pictures to illustrate (these are around 10 years old now - so it is not the only style of bushing/roller available these days I am sure).
Now, with many items "recommended" there is often a bun-fight over who is to pay (I regard that as slightly different than who is to "supply").
I have seen these bushings purchased, or rented. I have seen them "owned" by the rig or the service company or the operator.
The cost is usually insignificant when compared to NPT incurred via a damaged logging cable - one perspective.
Sometimes the Operator will say - "we are willing to pay for them, but we want you to procure them - it will be too lengthy to get our procurement team to set up an approved vendor and get approvals etc etc. Just buy/rent them and back-charge us"
If the contracts are long term, it might be more "reasonable" to expect the logging provider or drilling contractor to buy the item - but this is best done as a part of the tendering/contracting stage. I certainly do not feel that there is a right or wrong answer.
I guess the key elements of correct procurement are the specifications - bushings correct for the rig, and any wheel/pulley suitable for the logging provider's cable size and metallurgy (hardness)
Sometimes of course, (and not just for items like this) both the operator and drilling contractor tell the service company - "this is to help your service quality, you ought to pay".
For me, the 3 key considerations should be:
1. is this piece of kit a good idea and we want to have it available (whether it be for technical improvement, efficiency or safety)
2. Who is best placed to procure and order it so that we get the correct/suitable thing in the time frame we require?
3. Who will pay for it ultimately?
I would ALWAYS recommend obtaining a purpose-built, and/or designed and tested piece of kit, rather than modifying something else. Without the slotted bushing, the key is to ensure that the slips are aligned carefully so that the natural "gap" in the slip is where the cable is. I saw my first slotted bushing in the early 90s when I was a logging engineer - the logging cable had worn a groove in the rig's bushing over a series of jobs, and basically the drilling contractor said "you have damaged our bushing, you can keep it". So we took it to town, machined the groove to be uniform and the size we wanted, and then shipped the bushing out on all future pipe-conveyed jobs.