No embassy can demand any sponsored person to be forced to stay in the country of processing as a matter of policy but there is more to it than just the policy i.e. the ghost of your application follows you wherever you go ........... if the sponsored person leaves the country on a workpermit/student visa for a period of one year or more his/her file will be transferred to the destination country or the respective processing office. The sponsored person is always required to inform the CHC of any change in contact info ....... when the CHC staff will try to reach the sponsored person/applicant and wont find the person, they will either put the file in a cold storage or send a letter to the last known address to contact them ............hence it is a negative impact on the application .......... however if the person is lucky enough to get a work/student permit to a country where CHC takes far less time to process, the work permit/student visa can help get rid of CHC-ISB and they take around 3 months to transfer your file to new CHC........... please note that the aforementioned info (one year work permit/student visa and file transfer) is based on the response from CHC-ISB to my once upon a time request when i was considering to get student visa for my spouse to UK in order to get rid of CHC-ISB timeline ..........hope it helps