We have 10 HP t310 zero clients and I had to disable the two Thinprint services from Win7 64bit virtual machines in order to have a stabile network default printer for a user. Thinprint tries to change the default printer to a local (virtual locals included) printer. Maybe this is not the issue that you are having...
Also, have tried pushing a network printer for VMs through group policy... didn't work as expected. With PCs group policy succeeded installing the driver and the printer was deployed, but with View 5.1.2 VMs it seemed the group policy does not succeed installing the driver. We have now put the drivers of our printers to the base image; don't know however which one of these is enough or are both needed; a) using pnputil -a *.inf b) taking the printers into use including driver installation and then removing those printers from the base image - this gives the drivers to the base image's (win7) Windows Print Management view. It seemed likely that the pnputil -a *.inf for the printer drivers was not enough - that was a surprising result at least with one printer model. With PCs pnputil -a *inf has worked for us ok.
Could you tell a little bit more about how you are using location based printing with these zero clients?