[Vexx]

Either scenario is possible since Shiori *met* Yuuichi and Ayu in the park and knows about him.

So far, with the information presented in Kanon2k6 - the evidence doesn't really provide enough data to know whether Shiori or Yuuichi is the intended target. The weight kind of depends on whether you think Shiori is hoping that Kaori might have a change of heart if she sees her outside ... or that she could play mysterious girl and tweak Yuuichi's interest since she found him so entertaining on that first meeting in the park with Ayu. I think the weight is toward meeting Yuuichi after that fateful park meeting because she chose not to take that final action -- but that is only implied with the flashback in ep 18.