I think it's good!
I've never had an issue with baiting (i.e: people signing up, getting the things, and then cancelling their pledge before payment), but I know a lot of other people have, so a first-time charge upfront is a good idea, IMHO.
The thing about those genuinely supporting patrons is that they like giving you their money for your stuff, and the upfront charge would be for new supporters - new supporters who, hopefully, are genuine. And most Patreon-campaigns are structured in such a way that a lot of the content they get access to - like early pages, or sketchposts - are right there on the site, so signing up gets them instant access.
Really, it just means they pay you right away for something they're getting from you. It's not like you go to the grocery store and get a big bag of groceries without paying, take them home and eat them all, and then tell the storeowner you don't feel like paying for it.
I offer a bunch of PDFs for download for the higher tiers, and to avoid the cancellation issue, when a new patron on those higher tiers signs up, I always delay sending those links out until after they've been charged - which means they sometimes have to wait nearly a month to get them. If they were charged upfront instead, they'd get access immediately, which would make everyone happier.