I don't know what you mean by "90% problem", but unlike what your blog article suggests, Django's template engine escapes everything by default. You have to explicitly pass content through a filter to request that it not be escaped.
Based on the fact that the suggestions in your blog article could easily support someone forgetting the "|escape" on a variable, I would accuse your methodology of only solving the "90% problem".
Based on the fact that the suggestions in your blog article could easily support someone forgetting the "|escape" on a variable, I would accuse your methodology of only solving the "90% problem".