We are trying to have a "wildlife friendly" garden (at least that's our excuse for not having pristine flower beds and a beautiful lawn) so we don't use pesticides or weedkiller (we're weed-friendly, too) and we don't even do anything nasty to the slugs when they eat our lettuces. We've tried to remove anything which could cause problems for the lovely hedgehogs who visit each night, but we made a mistake which could have been fatal for another small creature.
A couple of months ago, we went away for a few days and asked our neighbour to feed the birds and hedgehogs while we were away. We put out a large, rectangular storage box on the patio, part full of water, so she could top up the bird baths and the hedgie bowls. After we came back, we stopped using the water in the box, but just left the box out. It has had various insects in it, but no major wildlife - the water is too deep and too far from the top for the birds to use it, and they have three nice shallow bird baths anyway. The box was too high for a hedgehog to climb into, so we didn't worry.
I was rather surprised this morning when I went out on to the patio to find a poor toad in the box, struggling to get out. He obviously jumped in, and it was too deep to jump out. Poor little chap. So, I gave him a leg up and he hopped out, and kindly posed for a few photos, apparently none the worse for wear, but it could have been a very different outcome. So we either dump the box or put a platform in to let the toads get out. I think we favour the latter.
P.S. If you are a fan of CSI and have access to all their wonderful computer technology, you'd be able to see what I look like, as there is a reflection of me in the toad's eye - click on the top photo for a closer view.