Think it's rather inappropriate, if the child is young enough not to understand the reference, should be stopped by its parent. Otherwise, if she looks quite young, possibly underage, then the parent is either irresponsible, out of touch with reality, or stupid and should have given their child better guidance. Unlike Fat Willy, which can be seen as a mildly amusing reference to make anatomy, the t-shirt the BJ logo suggests the child is advertising willingness to perform sexual acts on males. Those reading the message are not likely to know it's simply advertising a clothes brand and a bar.