When you look at an item, and it looks as if one might have pounded it to shape as from a piece of bread dough, or if it has fanciful contours and appendages all in solid glass..... it is not "blown".
if the item is an open shape, hollow sphere, bowl or ball shape, it was likely "blown". If the wall thickness is heavy, it probably had minimal blowing; if the wall thickness is quite thin, it would have started with thinner walled tube stock, but chances are it also had more intricate work done to it.
Claims of "blown" glass are supposed to lend an aura of respectability to a simple piece. That is probably not illegal, but perhaps now you can tell the difference.