Hello everyone!
I searched for an answer to my question, unfortunately didn't find one. So I hope you can shed some light on the matter.
I buy the premise, that Conan didn't find the spare pursuit glasses, despite his persistent personality. It's unlikely, but still possible.
But as far as I know, these glasses can only pursue the Detective Badgets and specialized transmitters... so, why on earth, if he didn't want Haibara to follow him and suspected that she had the spare glasses, didn't he just leave every kind of transmitter at home?
The only reason I can think of is, that in the worst-case-scenario Agasa needed a transmitter-signal to find him. However he doesn't use the glasses or any other tracking device, as far as I could see.
Well... I just wouldn't like the idea, that Gosho couldn't come up with a scenario to get Ai to the final showdown, that was in itself consistent. He is better than that.
So let me hear it! What did I miss?

