If the company thinks they have the right to my personal life because they pay me for 40 hours, then its slavery. Also, threatening me with firing because I refuse slavery is threatening my livelihood, and it's mafia mentality. If a manager thinks they have the right my personal time, I should have right to their personal time too. Traffic should go both way in a bridge.
I hire intelligent people, treat them as such, and expect intelligent behaviour in return. Part of the expectation is that everyone manages their own time responsibly. If they fail that management and have to work after hours, I do expect them to take the fall. There's no slavery and no mafia involved here; much to the contrary, it's a healthy work environment with historically excellent work/life balance.
Do you have this kind of system set up? If not, do you make it clear when you're hiring people that you're expecting them to occasionally do what is effectively uncompensated oncall on nights/weekends? That's the kind of thing you have to know going in in order to be able to compare like-for-like in competing offers.
There's a second level to this, which is the definition of an acceptable workload. That is company-cultural, and you'll have to take my word for it when I say it is acceptable. We have the position that in the long run it's best that people feel happy on the job, which requires workloads compatible with life outside the company.
I never ask my employees for overtime, never control their work hours. The typical work week that organically arises out of this is about 35 hours.
I would absolutely fire anyone who would close the laptop for the weekend and left a critical operation pending on Friday. It's about work ethics and personal responsibility of the outcome of personal work.