I don't mind getting invited to a shower for an additional child AS LONG AS THE SHOWER IS AFTER THE BABY IS BORN. I will not go if it is before because I feel that I have to bring a present to the shower and THEN if I go see the baby I have to bring ANOTHER present!
No to the diaper thing. I have gone to ONE shower that had that "game/option/etc." and I did bring a pack of diapers but I would NOT do it again. Afterwards I felt like it was joke that I brought a gift and THEN brought a $15 to $20 pack of diapers too....... PLUS, 2 of the women signed up for that prize because their "gift" was diapers when, in fact, you're expected to bring the pack of diaper ON TOP OF THE GIFT.