Assuming that their union is legally recognized: Their existing work arrangement is agreeable to Google. If the employees wish to continue with their existing

Assuming that their union is legally recognized: Their existing work arrangement is agreeable to Google. If the employees wish to continue with their existing work arrangement, only as a union, and then Google chooses to reject that, then that is sufficiently strong evidence that Google is rejecting their demand purely due to the existence of a union. That is illegal according to current US law. If they declare that they are not rejecting due to the existence of a union, then there is sufficiently strong evidence that they are not engaged in "honest dealing" as they are being dishonest with their motives. To engage in "honest dealing" with those facts either requires them to honestly disclose they are rejecting due to the existence of a union (which would be illegal), or extremely compelling extenuating circumstances showing why their existing work arrangement is now, coincidentally, untenable.