If the hotels were serious about asking us to MAGC ( as opposed to a strategy to reduce labour costs), then they might contemplate a few measures themselves, eg, ditch the ridiculous single use shampoo/conditioner/shower gel in favour of the permanent in-shower dispensers; also eliminate plastic straws and provide water in rooms in glass bottles.
I take my own products, up to the 100ml limit, because I don’t like the single use items. I activate the DND on arrival , regardless of MAGC points or not.