Whether it [the new moon] was clearly visi-ble, [or] whether it was not clearly visible, they could desecrate the Sabbath because of it.  R’ Yose says: If it was clearly visible, they could not desecrate the Sabbath because of it.

It happened that more than forty pairs [of witnesses] passed [on their way to beis din], and R’ Akiva detained them in Lod.  Rabban Gamliel sent him [the following message]: If you detain the public, you are placing a stumbling-block in their path for the future.