Oh my lord, I would totally say something. At its simplest form, it’s like littering on your property, which is disrespectful.
But on a larger level, your property is your liability, so if another parent or child happens to slip and hurt themselves on this liquid, that’s now your issue to deal with. The same goes with the bees swarming the pop, it creates more opportunities for children to be stung.
And of course lastly, it has damaged your driveway.
If I saw that happen on my driveway, I’d hand the parent a hose or a scrubbing brush and a pail, and tell them to clean it up.