@wonder2wonder said:

if you knew (The Doctor knows, but never forewarns) that:

1. you will never see your family and friends again.

2. you will not return to your own time or place and left stranded to survive on your own.

3. you will die or encounter an even worse fate.

After watching so many "Doctor Who" episodes, I think that it is fun to just do that: watch.

His travels are not like one of those thrillseeking, fun-loving, adventurous vacations you go on and then return home, suffering only from a slight sunburn and an itchy mosquito bite, and you sit down sipping a warm cup of tea, chit-chatting with friends and family, sharing pictures, vids and tall stories about your heroic deeds and the amazing sights.

And if you do return "safe", your memory is wiped clean.

All the Doctor's companions have trusted him and followed him, almost always, blindly to wherever and whenever he goes.

Should he not at least tell them what has happened to his previous companions? Or would that be spoiling the surprise?

I suppose he could, in addition to telling them of the vast MAJORITY of companions who are just fine. Sarah Jane ring a bell? #7's companions are fine, Grace from the TV movie counts she's fine, I could go on. It's really gloom and doom and a companion must meet a sad fate under Moffat, but its not indicative of what came before and hopefully not what will come after Moffat is gone.