The Meridiens seem to me to be more holiday oriented hotels with presumably a fair chunk of rooms sold via Tour Ops. I can understand not wanting to partcipate in SPG if this is the positioning of the property, i.e. that few additional revenue guests would come to the property because of SPG, but there would be a need to accomodate redemptions.

The Westin seems to be positioned differently however so this doesnt make sense to me. I do not know many frequent business travellers who would choose a property which excludes frequent guest points and benefits over one that allows them. That said there is a proportion of business travellers who do not join schemes, this is not because of their wealth it is because they are infrequent or inexperienced travellers. Such people do not often become repeat guests IMHO.