I'm sure there isn't a practical solution for this. I've found it's hard to read old posts that have quotes in them. Instead of being captioned nicely like new posts it's just read as text and is hard to distinguish sometimes what is what. The problem is compounded if I am reading old posts on my phone.
No way around it that I'm aware of, unfortunately. When the old CuteCast database was converted over to SQL, BBCode was turned off by default in those posts to avoid potential issues. If you find an old thread that is quoted properly, it probably means I was there and cleaned it up manually.