I have a few decades of experience of walking (often barefoot) onto flowering lawns/meadows and I’ve never been stung by a bee. Unless you disturb their nest, which won’t be in the lawn, bees will do their best to avoid you. Well, European honey bees are harmless at least. Bumblebees are harmless as well. I have been stung a few times by wasps, but those incidents were not lawn related in any way.

If the lawn is more grown out and I’ve walked through it, then I always worry about ticks and I check my legs afterwards, because of Lyme disease.