My father's red lines:
Buy our council house.
Supervise any fellow worker outside a democratically controlled workplace.
Own a car (excessively individualistic, undermines the case for public transport)
Private healthcare (a theoretical objection as he could barely afford new bootlaces never mind botox)
Private education (compensated for this by making me and my sister do about 6 hours of homework every night)
Never buy anything on credit or have a bank account. (There was also some doctrinal issue with insurance but my mother nagged him into submission on that.)
Never went in a bookies, and very rarely into a pub as he thought gambling and alcohol attenuated class militancy.
He would, however, cross picket lines of unions that he suspected of ideological deviancy. Whichever union represented the workshy arseholes in the local branch library was in this category.