I hope people don't give into this propaganda and feel socially pressured into getting an e-tag. If you ask me, I actually think this is a clever move by SANRAL. Not many people use their brains, and if they hear that 500 000 people already bought e-tags, they're not gonna wonder whether SANRAL is lying - they're gonna look for the closest place to buy an e-tag. If the public wasn't so hell-bent on stopping e-tolling, SANRAL's statement would have held a hell of a lot more weight.
EDIT:
By the way, the article's title feels rather misleading. I believe it should be named "Half a million e-tags sold says SANRAL" or "SANRAL: Half a million e-tags sold".
I don't get why the thread title is so clear ("Half a million e-tags sold - SANRAL") while the article title is so misleading ("E-tags: half a million sold"). I really don't like it.