The main case where I find it easy to run into the "wait 60 seconds between reporting posts" is when a newly created would-be spammer account is trying to post-pad its way towards being able to post URLs, or some other somesuch threshold, and has run into the "new accounts are limited to 5 posts for the first 24 hours" limit.

The wiki on this thread: Report spam / spammer post issues here (PLEASE read wikipost) says, in part* "If it's multiple posts by the same person in different fora, one alert per forum is appreciated - it allows a more complete and quicker response." Often that's 5 different forums, meaning 5 different RBPs and having to wait out the 60 second circuit breaker 5x if you feel like reporting each one.

*literally -- it's where the "show more" cutoff appears and was previously truncated entirely at this point until I fixed it, which is what led to my other recent post in the "broken wikis" thread...