Has anyone used CiviCRM on a 10" tablet?
The main factor is probably the resolution of the tablet rather than its size, but the UI is in general meant to be used with a keyboard and a mouse (or very very pointy fingers ;)

For the mobiles, they have been several projects to provide a subset of CiviCRM features available.


One is cividroid, an android application from the latest google summer of code https://forum.civicrm.org/index.php?topic=36037.0
Another is an extension on the server that adds a few "mobile friendly" pages https://civicrm.org/extensions/civimobile


If the aim for the tablet is "only" to do the registration, using drupal as the CMS+bootstrap as the theme+webform+webform civicrm should allow you to have a user friendly form tailored to your need that will push the data in civicrm (create the contact, the activity and the case for instance), to be used later with the "full" civicrm from a laptop

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