I haven't seen anything to say the witness had not been subpoenaed. The usual Crown prosecutor practice is to subpoena all non-police witnesses. In any event, s. 704 does not talk about subpoenas, it talks of recognizances. Given how rare such cases are, there isn't an established test for "about to abscond". 

That being said, I repeat that it appears that the proper procedures were not followed in this case.