There's a lack of standardization when it comes to tags and when or when not to use a period. I've listed some particular examples below, although there might be some missing.
Standardized
1. Acronym
2. Version
Non-Standardized
3. Initials
4. Mister/Misses/Ms
5. Junior
6. Doctor
7. Saint
8. Mark
9. Number
My preference would be to...
- Not use a period for...
- #3 since as long as it's surrounded by underscores (spaces), it'll be clear that it's an initial so the period would be unnecessary
- #2,#4-8 since those 2-3 letter shorthands are pretty common and so the period wouldn't be necessary to clarify what they mean
- Use a period for...
- #1 since tags aren't capitalized, it's impossible to denote a tag is an acronym otherwise
- #9 since "no" can mean many things without the period, to include the Japanese の
Thoughts?