G.,
I see your 3 1/2 years old point of view perfectly.
Probably because I feel the same way when a carrier that I have been loyal to for years offers a special incentive to a new customer and I receive not even a thank you.
Questions:
Why does your 2 1/2 year old get a plastic bug EVERYTIME
she goes potty? If that is something that also would make your 3 1/2 year old happy, could she not receive one for using the bathroom also? Are you going to cut your 2 1/2 year old off cold turkey when going to the bathroom is a habit like appearly you have with your older child?
What I would suggest is you treat both girls equally.
The sticker system could work for both. Perhaps its every three stickers instead of five.
I invite you to see your world through your 3 1/2 year old's eyes, not only with this one. Something tells me that this is only the tip of the iceberg.
With my whole heart,
C. TLC (Transition Life Coach)
Loving Connections LLC