Analytics implementations decay through naming. Six months in, the event list contains newsletter_signup, newsletterSignup and NewsletterSignUp, and each is a separate row in every report.
Agree the convention before the build
Decide the casing once, write it in the tracking specification, and convert the whole event list to that form before handing it to whoever implements it. Most platforms want camelCase for parameters; check yours and commit.
Why retrofitting is expensive
Historical data keeps the old names forever. Renaming an event does not rename the events already collected, so every year-on-year comparison has to union two names — for as long as the comparison window includes the change.
Structure the name too
categoryActionLabel ordering keeps related events adjacent when the list is sorted alphabetically. On a property with three hundred events, that ordering is the difference between a browsable list and an unusable one.
Try it: Convert to camelCase on SeoWolf's Notepad.