Alice reminds Jan to wear her glasses for reading. However, when Jan got glasses in The Not-So-Rose-Colored Glasses (1971), she appears to need them to see distances, since she wrecks her bike when she isn't wearing them.
Carol punishes Marcia for leaving the record player on all night, and she can't use the stereo for a whole week. This implies that Carol and Mike owned the stereo. But it was Alice's stereo, as she won it as a prize in the Everpress Fabric Jingle Contest." ["The Tattletale", (#2.10)]
Right before Alice discovers that Bobby and Cindy are nude, Cindy is shown from the front with her arms crossed, but when the camera angle switches to behind, both arms are down at her sides.
Peter tosses the light, plastic Frisbee inside the house and shatters Mrs. Brady's lamp. But his casual, not-so-strong toss was further weakened when the Frisbee deflected off a few walls. The Frisbee then simply fell downwards rather gently. There's no way it could have shattered the lamp or even knocked it over. Plus, the drop of the Frisbee is much lower than where the lamp would have been on the small table.
Cindy and Bobby are headed to a neighbor's house to skinny-dip in their pool. Olsen and Lookinland were 11 and 12; most tweens would be mortified if their opposite-sex siblings saw them naked, so this idea is far-fetched.
When Peter tosses the Frisbee indoors, the lamp can be heard shattering (off-camera) while the Frisbee is still in view.