If you want no misunderstandings, be explicit. This applies to YAML and life in general. There's an annoying but fairly accurate saying about assumptions that

If you want no misunderstandings, be explicit. This applies to YAML and life in general. There's an annoying but fairly accurate saying about assumptions that applies. If you want something to be a specific type, you better have an explicit way of indicating that. If you say quotes will always indicate a string, great. Of course we know it's not that simple, since there are character sets to consider. The safest answer is to do something like XML with DTDs. But that imposes a LOT of overhead. Naturally we hate that, so we make some "convention over configuration" choices. But eventually, we hit a point where the invisible magic bites us. This is one case where tests would catch the problem, if those tests are thorough enough - explicitly testing every possibility or better yet, generative testing.