No.

Because how would the 'soldiers' know exactly when Michael went into the bathroom? Remember, this is 1946.

And suppose everyone agreed on an exact time when he would get up to go to the bathroom? Do you think Sollozzo would be just a tiny bit suspicious that Michael checks his watch and then leaves the table?

And suppose some 'soldier' is watching from across the street to see just when Michael gets up. You think Sollozzo doesn't have the whole block swept and a lookout for something like that already covered?

The only way to get this done was to have them completely trusting of Michael and the Corleone Family.

Apple