I think it really depends on what sort of work the cron jobs are doing.
For instance, I once had a system where people could request accounts to be created / modified / whatever ... and instead of giving the webserver direct access to do things, it wrote files to a queue to be a processed. Once every 5 minutes, the files in the queue were checked, and processed (well, after the cron job checked to make sure the process wasn't still running from the last time it was kicked off)
As it's annoying to get e-mails every 5 minutes, each of the sub-tasks got logged to a seperate file (eg, new user accounts, new organizational accounts, new user accounts that were forced in by the helpdesk, changes in associations between user & org accounts, modifications to org accounts, etc, etc.). Every hour during the work day, and less frequently at night, another process looked through the log files, and generated a report -- errors first, then other non-normal events (eg, people forcing accounts through, items in the queue that were more than an hour old and hadn't been processed, etc.). If there weren't any changes in that hour, it didn't report anything. (which was typical through most of the year ... it was a university, so most people came in at the change of semesters).
The only time that the cron job that ran every 5 minutes would report immediately is if something really bad happened. (eg, couldn't connect to the LDAP server or the other databases, or couldn't FTP necessary files to the host where the account was being created, or the process that started 5 minutes before was still active)