They needed a reason for Wally to be unavailable when Eddie got hold of Beaver’s report card and changed the mark. Wally tells the guys he has to change his clothes. I don’t think Wally ever changes his clothes when he returns from school. This time he had to have a reason to go upstairs. Did anyone notice if he changed his clothes? He didn’t have any track practice because he was home early. It would have been better if his reason to go upstairs was to find something in his room.

He did change clothes, but I checked the time, because it seemed like a lot of time elapsed for him to do it (it was around 3-1/2 minutes). That's a lot of time for a guy to change. Maybe he did some of his calculus while he was up there.

Yes, it was just an excuse to get him away from the scene. No real reason to change, especially since they didn't know what they were going to do.

Yes, it was just an excuse to get him away from the scene. No real reason to change, especially since they didn't know what they were going to do.

Four other times where they had to get Wally out of the scene so Eddie could give "advice" to Beaver:

“Beaver, the Model” – Wally goes downstairs to get something to eat for Eddie while Eddie advises Beaver to sign up for the modeling agency
“Beaver’s Accordion” – Wally takes a shower after painting while Eddie advises Beaver to send for the accordion
“More Blessed to Give” – Wally goes “to get the car” while Eddie advises Beaver to give the locket to a girl instead of June
“Don Juan Beaver” – Wally gets a dictionary for while Eddie advises Beaver to be obnoxious to Peggy so she’ll break their date to the dance

And, another time, in "Beaver, the Sheep Dog," Wally is right in the room when Eddie advises Beaver to insult Shirley.

That’s right. They really think up things for Wally to do. How about in Night in the Woods. Eddie, Lumpy and Wally are out front of the house. Gilbert and Beaver leave for school. Wally has said he can’t go with Eddie and Lumpy he’ll be camping. Wally tells them he forgot a book and goes in the house. Eddie tells Lumpy he has a plan to scare the campers on Saturday and Wally will be available Sunday for the date.