I have asked a similar question here and got some answers, so first of all sorry for making you people bother once again.
But I have an argument this time. First I will
Apples iPhone Human Interface Guidelines about alert views clearly states:
The infrequency with which alerts appear helps users take them seriously. Be sure to > minimize the number of alerts your application displays and ensure that each one offers > critical information and useful choices. In general, try to avoid creating alerts that:
Update users on tasks that are progressing normally. Instead, consider using a progress view or an activity indicator to provide progress-related feedback to users (these controls are described in “Progress Views” and “Activity Indicators”).
Ask for confirmation of user-initiated actions.To get confirmation for an action the user initiated, even a potentially risky action such as deleting a contact, you should use an action sheet (described next in “Using Action Sheets”).
Inform users of errors or problems about which they can do nothing. Although it might be necessary to use an alert to tell users about a critical problem they can’t fix, it’s better to integrate such information into the user interface, if possible. For example, instead of telling users every time a server connection fails, display the time of the last successful connection.
So, my advice, the time waiting for a potential rejection isn't worth your time. Don't risk it.