This was in the WFAANZ news letter a little while ago. (Window film association of Australia and New Zealand)
Tiguan tint trouble
If an owner of a VW Tiguan come into your workshop wanting tint on the rear screen – would you do it? Many tinters wouldn’t to avoid potential dramas down the line.
The Tiguan Owner’s Manual advises against putting stickers of any kind on the inside surface of the rear screen, as removal of such could damage the window heating system.
So, before you touch the rear screen of a Tiguan – always advise your customer of this recommendation. If they still want to proceed, have them sign a waiver. If the film ever needs to be removed (for whatever reason) and the demister bars are damaged during the removal, the entire rear window may need to be replaced.