There is an Out of Box Business Rule, which is part of Demand Management, called 'Validate Assessment Metrics', which prohibits fields like Risk, Value, Strategic Alignment, Cost and Size from having values lower than 0 and greater than 10. This Business Rule, however, runs only on Update. This means that, if a Demand is inserted with values higher than 10, the Business Rule will not trigger, and the action will not be aborted.
The Business Rule Validate Assessment Metrics only triggers on Update.
1. Navigate to your Validate Assessment Metrics
2. Navigate to the 'When to run' section
3. Check 'Insert'