I’m pretty sure there was an organized tribute while Schulz was still around. Dilbert had a complicated pun involving cashews before a drug test, which made Dilbert think of Charlie Brown (Pee Nuts); Luann had a sight gag explaining how Snoopy stayed on top of the doghouse; and Mallard Fillmore sneeringly quoted an old Linus joke about bringing the more fortunate down to his level (and incorrectly attributed it to Charlie Brown in the bargain).
I’m pretty sure there was an organized tribute while Schulz was still around. Dilbert had a complicated pun involving cashews before a drug test, which made Dilbert think of Charlie Brown (Pee Nuts); Luann had a sight gag explaining how Snoopy stayed on top of the doghouse; and Mallard Fillmore sneeringly quoted an old Linus joke about bringing the more fortunate down to his level (and incorrectly attributed it to Charlie Brown in the bargain).