Crystal: passing parameters to child reports

Say you only want to ask the user for a report parameter once and want to use the parameter in multiple reports. The best way I've found to do this is:

1. Create the parameter in the parent report
2. Link the parameter to any ole field in the child report
3. Remove the parameter in any selection criteria in the child report (unless you do really want it used)
4. Consume the parameter in calculated fields