I prefer to work with models who don't have chaperones. In the past where chaperones have been present, they interfere with the shoot, answer for the model when I ask questions / discuss ideas and generally hover around me as if im about to rape / murder her. One even turned up in a seperate car to the model 10mins later!! The shoots without chaperones have been much more relaxed and enjoyable and productive. I know my situation as a 'hobby' photographer is somewhat different to the 'pro' photographers here, but I would like to think that two mature adults (no matter of experience) working together on a project, both with clear references, contact details, pre shoot chat is enough and if any side is unsure of the shoot then cancel.
I do still work with models with chaperones present though and of course chaperones have their place esp for models who are minors, new to the work, or working with a photographer with no references, samples of work etc etc.
One thing I don't like and to be fair I've not seen on this site are the models who seem to think all photographers are a danger and almost state this on their profiles, hence their reasoning for using chaperones, or those who mention 'I'm here for modelling not dating / sex etc'. Any model with these on their profile is for me immediatley taken off the consideration to work with list, as it prob says more about their choices of dodgy photographers to work with than anything else!!