ABS can make braking safer in some panic situations by allowing a certain degree of steering control. The problem is if it malfunctions, it can actually make the brakes very unsafe, compared to a vehicle that never had ABS.
With an old vehicle, it's often very difficult or prohibitive to repair, because an intermittent ABS failure can be very difficult to track down, skilled mechanics able to properly diagnose and repair the system may be hard to find, and the parts to repair an aged ABS system are very expensive and/or no longer availible.

OTOH, I would never remove or disable an ABS system because of the potential liability issues and I have refused to do so when asked by others.
Since all my own vehicles are 'old', I've avoided this problem by only acquiring vehicles built without ABS.
Unfortunately, owners of old vehicles with a failed ABS are faced with a Hobson's choice - operate a possibly unsafe vehicle, try to get it fixed, or face the consequences if they disable the system.

The irony with all this is continuing to drive a vehicle with a failed ABS could be much more dangerous than having the system disabled.
Wouldn't the owner of a car with a bad ABS system be just as liable as the owner of a car with the ABS removed or disabled?

Happy Motoring, Mark

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DrDKW