The only time I have experienced removal of tints was whilst riding as a passenger in a car that had illegal tints. The driver was stopped by the Police, they checked the light level using a meter, decided that the % was illegal and proceeded to strip off the tint. They opened the window and used a sharp knife to release an edge, then pulled a strip off, leaving a very ugly looking window. Despite the protests of the owner, apparently they are quite at liberty and allowed by law, to do this as a means of ensuring that the owner is prompted into clearing off the rest.
As regards glue. The professional window tinters do not use glue. The film is floated on using only water, much like the transfers on the old Airfix model aeroplanes. Which is why the Police (as above) were able to strip off a chunk so easily. If the installer of your tints have used glue, then I would suggest that they were not professionally done and could cause you big problems. Are there any visible bubbles/creases that you could insert a craft knife into to start you off ?