far as I know the pro's can get them from anywhere, there's gonna by some, Bell I think, who has got his bats from Hawk for ages. As long as the right sponsor stickers are on there no one cares.
Some of them get big money for sponsorship so even if they have to pay a batmaker something for one of theirs it's small change. They might even get given them who knows.
One of my ex team mates is now contracted to Kent and I saw an advertising pic of him with some lovely H4L gear the other day
that reminds me......I must contact him and ask him if he has any spares, er no, how he's getting on at Kent !!