Reference for Bava Kamma 194:5
ת"ש אין מחללין על מעות של כאן והן בבבל ושל בבל והן כאן של בבל והן בבבל מחללין קתני מיהת אין מחללין על מעות של כאן והן בבבל אע"ג דסופו למיסק להתם
— He, however, said to him that we were dealing here with a case where the Governments of the different provinces were not antagonistic to one another. But since this implies that the statement of Samuel [as explained by R. Nahman] referred to the case where the Governments of the different provinces were antagonistic to one another, how would it be possible to bring the coins [to the province where they still have currency]?<span class="x" onmousemove="('comment',' Even though one had occasion to go there. ');"><sup>9</sup></span> — They could be brought there with some difficulty, as where no thorough search was made at the frontier though if the coins were to be discovered there would be trouble.