I don't know the same people that get mad at a corporation for allegedly "cheating the system" in some way don't find this sort of thing offensive, but weirdly they don't seem to at all.
If this is in San Francisco, report them to the landlord or the city so they can be evicted. Tenants who abuse the system worsen the housing market for everyone.
That's generally illegal, unless the subtenant is paying no more than the tenant is in rent. Every tenant who does this in San Francisco can be, and ought to be, immediately evicted. There is zero economic/social justification for abuse of rent control.
Yes, subletting for more than main tenants rent is illegal, but considering how hard it is to find apartments, most subletters just let it be.
