Wise words.
And actually I’m always very much tempted to correct the often-used apostrophe before a genitive-s in German signage (»John’s Bar« would be »Johns Bar« in German). It’s appropriately called »Deppen-Apostroph« in German. ;-) Many people now even use an apostrophe before a plural-s. Makes me cringe. Punctuation police indeed…
100% YES to using a style guide (and a glossary) as a writer!