[CompSci87]

has Stanford learned to not offer kids unless they sign up for AP classes their Senior year of High School?

Offers are always contingent on admission. If there's someone Stanford really wants, it would make no sense to say, "Go sign up for AP classes, and maybe we'll offer you a scholarship if you do well." The formula would be more like "We're offering you a scholarship contingent on admission -- and at Stanford, football players are not guaranteed admission! You'll need to sign up for AP classes, get a good SAT score, write good essays on your application, get good recommendations, etc."

[CompSci87]

has Stanford learned to not offer kids unless they sign up for AP classes their Senior year of High School?

Offers are always contingent on admission. If there's someone Stanford really wants, it would make no sense to say, "Go sign up for AP classes, and maybe we'll offer you a scholarship if you do well." The formula would be more like "We're offering you a scholarship contingent on admission -- and at Stanford, football players are not guaranteed admission! You'll need to sign up for AP classes, get a good SAT score, write good essays on your application, get good recommendations, etc."