Check this query before I run it

Before running anything expensive, destructive, or going into a report.

Review this query for correctness. I have not run it yet. Do not tell me it looks good.

Check in this order:
1. **Grain**: what is one output row? Does any join multiply rows before aggregation, inflating the sums?
2. **Filters**: does any WHERE condition on an outer-joined table silently convert it to an inner join?
3. **NULLs**: in join keys, in NOT IN lists, in comparisons, inside aggregates.
4. **Dates**: inclusive or exclusive boundaries, timezone, whether BETWEEN is dropping the last day.
5. **Aggregates**: COUNT(*) against COUNT(column), averages of averages, SUM over a duplicated row set.
6. **Destructive statements**: any UPDATE or DELETE without the WHERE clause I intended, or whose WHERE matches more than I think.

Give a verdict: safe to run, run with caveats, or do not run. Then give me one cheap query that verifies your main concern before I run the real one.

Query:

Correctness checks. Catching the join that duplicates rows, the NULL that drops them, and the GROUP BY that lies.