Use of Indirect Object Pronouns with Verbs of Request/Recommendation

[Jodi Kristen]

At one time, I learned that with verbs of recommendation or request (like aconsejar or recomendar), an indirect object pronoun was required.

Example: Le aconsejo a Juan que estudie un poco más.

Now I am seeing many of these sentences without an indirect object pronoun, even in the textbook I teach from.

Example: Recomendamos que Uds. hablen con Marisol.

I can't seem to find any rhyme or reason as to whether or not one should use an indirect object pronoun here. 

Are both using or not using an indirect object pronoun acceptable with verbs of recommendation? Is it just a matter of preference as long as the sentence is structurally set up like one of the above sentences?

Thank you for your help!

[Lorei]

En la segunda oración que pones veo la palabra "que", gracias a la cual no se necesita la preposición "a".