MacroDroid is really open in this way and no matter what you do or set macro edit screen will always appear after import, so they will be able to see and change the macro. Only way would be to have their mobiles in your hand and lock category with macros you don't want them to edit. I think this is actually good behaviour because it prevents you or any other people from importing a macro that would do some nasty things behind the scenes and I don't want to blame you exactly, but it would really be possible to collect and send some personal informations with MacroDroid especially if users wouldn't be able to see contents of macro.
