[Omin]

I think op goes too far by including trailing slashes, but being liberal in what you accept (Postel's law) is a bad idea as the last few decades of the web have shown. Once you accept things, you are locked into supporting them forever lest you break compatibility. When there are multiple different implementations of a standard, they grow incompatible over time.

[lifeonlars]

Well, the web has been very successful in the last few decades. Arguably at least part of this success has been due to Postel's law since, for example, browsers interpreting HTML on a best effort basis has allowed for both diversity and innovation. Comparing the rapid adoption of the web to the failures of numerous closed and strongly specified protocols provides some empirical basis for this.

[cellularmitosis]

Accepting and ignoring doesn't lock you into anything.