Tipping on tours and bus drivers

[MSEm]

What is ACL policy on tour guides and drivers soliciting tips?

[Loveh2ofl]

They welcome you to tip tour guides and drivers at your own discretion.  

 

Written on description of the shore excursions (online) - I printed it out but don't remember the link.

 

"Tipping policy:  Driver and guide gratuities are appreciated but at the discretion of each guest"

[MSEm]

Thank you.  Trying to calculate the amount of real cash need on the cruise.