Probably at least as effective and a lot shorter:
"I'd love to go out with you, but that would violate the terms of my parole. But if you can wait a year, my sentence for poisoning my wife will be finished and you can come round for dinner."
Some mobile phones can be made to ring as if someone is calling, providing a convenient excuse to leave a meeting or get away from someone. Pretend to answer, then say something like "No, the drugs are supposed to arrive tomorrow
" or "Good, tell the snipers to stand by and move the first team into place. I'm looking at the suspect now".
(Disclaimer: I have never actually tried any of these, so I don't know for sure how effective they will be or what to tell the police later.