11 month old foraging for pebbles - how dangerous?

[SpawnHorcrux]

This is a bit of a trivial question really, but I's like to know if I'm being over-protective.

DS (11 mo) is just obsessed with finding small stones and putting them in his mouth. It makes it very difficult to relax in the garden, because he spends the whole time sneaking off to find and chew pebbles (and I have a maniac DD who requires lots of attention, so I can't keep an eye on him all the time).

Are small stones a choking risk? They look like they would be, but I haven't come across anyone else who's had pebble-eating DCs, so I don't know.

Yes, they are.

As are whole cherry toms and grapes at this age.

Not sure what the solution is, though

Yes...I thought that was probably the case. Bugger.

We have gravel in our garden and dd2(18 months) always makes a bee line for it and stuffs it in her mouth,she thinks it is funny and runs away from us.
Drives us crackers,as we cannot sit in the garden or turn away for a minute.

Yes, DS thinks it is the height of wit when he's smuggling pebbles. He can barely control his grin as he sees me coming to pop it out of his mouth.

I have this with a 10 month old now.
ANY tiny, hard chokeable object goes straight in her mouth. She spots them from miles away! Mine doesnt think shes the height of wit (thats so funny, by the way), but shell see me approaching and get really angry, knowing Im about to take it off her.
When does this phase end? Its very stressful.

The bad news is that my nearly 18 month old hasn't grown out of this yet. I tend not to chase her when she's got one in her mouth, as I think it's more likely that she'll choke on it whilst running than whilst just sitting/standing and playing.