We have had some problems with customers, who made cron jobs like this:

• 9 * * *

This means, that the cron job runs every minute, at 9 'o clock, which usually isn't what the customer would want. Instead it should have looked like this:

0 9 * * *

Therefore we'd like to suggest the making of a simple warning message, that states the fact that the cron job will run every minute of the chosen hour, rather than once. Perhaps it could actually display a small example, just like my second 'copy paste' of the cron job.