The Moodle installation documentation says that the following are required for Moodle:
Going by these requirements, a person new to Moodle can choose a hosting company and may later find that if PHP safe mode is on, there are so many things he/she cannot do and the installation of Moodle may be useless for him/her.
I would suggest that the requirement of PHP safe mode off needs to be explicitly stated in the installation documentation.