I don't promote nefariously abusing what I'm about to tell you but use it if you feel justified in doing so...
You know how you have to pay R5 for 1 hour's worth of undercover parking at Westwood? Well, shopping at Pick 'n' Pay gives you 90 minutes free parking but what if you end up being delayed in the queues to pay for your shopping and the 90 minutes expires? Simple: swipe your ticket again!
You see, the system at Westwood seems to work by setting your timer back 90 minutes (e.g. 12h00 arrival becomes an effective 13h30 arrival so at 12h45 the system technically sees you as 'not having arrived yet') but when the 90 minutes is up the system seems to just count up from zero again (you've arrived at 13h30 so it counts as normal from then) so if you then swipe your ticket for another 90 minutes of free parking it thinks you're resetting another 90 minutes (e.g. 13h30 'arrival' becomes an effective 15h00 arrival).
If you are already within the 90 minute cycle then swiping your ticket again has no effect. You have to wait for the 90 minute cycle to end before doing this again.
And yes, I've done it myself and have had a friend do it too so it definitely works.
Feel free to +1 me if this post is helpful.