I just tested the mail function with PHP on all the free servers a few hours ago with 5 emails each to gmail. Every email made it through and it was about 50/50 went to the spam box, however my emails were just random text.
All cron emails are automatically discarded by our mail server. This was due to people getting the mail IPs blacklisted... say 1,000 people run a cron at the same time and they all have a gmail account. 1,000 emails blasted to gmail at the same time with mostly junk in the subject\body = blacklisted for a few hours.