I think the short answer is we will need to wait and see. I could understand a decision to use a fully encrypted system on the 700MHz trunker with the exception of (maybe?) some mutual aid talkgroups. LAPD has an elaborate UHF system that just simply works for their needs. The 700MHz frequency reservations and system build out was a result of the possible loss of UHF T-Band (470-512) which LAPD, LASD, and other public safety agencies utilize in the LA basin. Fortunately that was killed off with legislation finally to remove that action.
The LAPD is fully equipped with multi-band portables and mobiles to use either resource. Past comments from reliable sources have stated that the 700MHz system may be used for special ops and events. Time will tell...