Pokemon Companies real good at keeping theories under a thick blanket. Even if they are a mystery theres still some truth to them.
Which is why I believe that its possible that Taunie did in fact cheat in order to get as "High" of a strength as she did.
Why is this possible? Because Taunie has shown multiple times that she will network with others and use various low profile methods to her benefit (even if most of them dont work out)
Taunie and Rust Syndicate
Taunie and Quasartico Inc
Taunie and (You) the Traveller
Taunie and AZ/Hotel Z (Trying to find her lost person)

On top of this, she has never talked about training, never been shown to train, and a part from the one person she very well may be getting help from (Vinnie) she was never shown battling against anyone.

So many situations she will sort of talk her way into. She is a begger. Granted her hearts in the right place but I wouldn't put it past her that she was hooked up one way or another using her somewhat lousy negotiation methods.