The last sentence in this story suggests to me that Tony T is well aware of all the negative speculation but is fully intending to fund season 5 and therefore is keen to make sure not going to Mexico is not misconstrued as the series falling over:
http://www.a1gp.com/News/NewsArticle.aspx?newsId=43022
And this story says a lot more about the local Surfers organisation than about A1GP, but is still a positive sign:
http://www.goldcoast.com.au/article/...t-supergp.html
I still suspect that A1GP are stretching payments as far as possible, to the annoyance of more than a few people, but the funding is there in the background in case the .... hits the fan.