Edit the incident/service template from which the asset needs to be hidden, choose Field & Form Rule tab. Create a rule "On Load" with the below script.
jQuery('[name=selectedCIs]').parents('div.mb0').hide();
//Hiding the asset in details page (In-line Edit)
try{
jQuery('#multiasset').parents().eq(0).hide();
}catch(e){}
and save.
The field asset is still visible at template loading.
Thank you!