No, its fine - clip the spent flowerheads off directly behind the stem.

The only problem is, these trees don't stay small and what are you going to do when you can't reach to cut them off. The only sensible thing to do is to teach children who visit, that they are poisonous. That's what my parents did with all poisonous plants and there are an awful lot of them in the garden.

I agree Camomile death from accidental ingestion of a poisonous plant is highly unusual. I grew up with laburnums and I have one in my present garden which I planted 12-14 years ago. I leave them on as I do not dislike them - I couldnt reach them anyway.

I had a laburnum when my kids were small, it was self set and already there when I moved in, quite small at the time. I kept it as a small 'lollipop' for 12 years, with a trunk about 4 feet, and every year I'd cut off not only the flowers, but prune back all the branches. Worked well, probably huge by now, I moved out of there years ago. Its sadly not difficult to inadvertently ingest a seed if your kids play out there and have toys around.