would said recycle bin have a cap (as in, it would keep say, the last 20 reports you deleted), or would you have to manually go and delete the reports AGAIN after deleting them once? Honestly, I can't see much of a reason for this: if you wanted to do this as it were you could set it up as it is: just create a "Recycle Bin" group for your reports and move everything there rather than deleting.
I can see two problems with this:
1) Limited Usefulness: The amount of times you would actually use this feature would be few and far between (well, for me anyway). The rest of the time, it would simply mean that it'd take more work simply to delete something, which when you're deleting 1k+ reports of your fakes hitting someone else, can get a bit tedious. In what situations, other than the accidental deletion of a report you didn't mean to delete, would this actually be useful, and how many reports out of the thousands that you might be deleting in a week (late game certainly) would you actually want to restore?
2) Message Space: If everyone were to have a recycle bin, it would at least double the amount of server space being taken up by reports, especially if people forget to empty their recycle bin if they want to actually delete reports. More server space => either slower servers, more chance of lag, and less space for possibly more useful upgrades and additions.
Essentially, I think it would be more of a hindrance one a redular basis than the odd time it would actually be helpful.