Population control measures serve three purposes.
First of all, they hamper the movement of #resistance members (perhaps even #tracking and #identifying them).
Second, they serve to #harass and #intimidate resistance #supporters and #sympathisers.
And third, they intimidate members of the #public and force them to change their lives to accommodate the desires of those in power.
Often population control methods are "#security theatre" and allow #governments to flex their muscles and project #authoritarian power with the goal of cowing people into #compliance.
Faced with such measures, resistance movements have several options.
Aboveground resistance movements and their allies can use the repression to gain support from the general population, appealing to shared public concerns like #privacy, #freedom of movement, genuine #security, and so on. If possible, a campaign of #civildisobedience could be organised against population control measures.