I am glad you pointed that option out. I was completely confused by "pretend to be busy" playing a recording. My mindset is that is if a phone is actually busy, and the voicemail is enabled, it would go directly there, and if the mailbox was disabled, it would send a 486 back. The message confused me since I cannot think of a situation where it would normally play it. Honestly I think the following 4 Spam options would be the most logical, and cover any need:
-Send to Voicemail
-Send Busy (sends 486, or 500 depending on trunk setting)
-Redirect (and give a field to redirect to)
-Ask for name