Time Travel

I've mentioned this before.  Physicists like to talk about time travel because according to the current standard model, it is theoretically possible.  But I suspect that either this will turn out not to be the case or that like a lot of things, it would be so technologically difficult, even for the most advanced civilization, that it is essentially impossible.  As far as we know (at least according to public knowledge and conventional scientific/historical understanding), no one has time-traveled into our historical timeline from the future or between points within our historical timeline.  Or if they have they've done it without being detected (either directly or in terms of causing anomalies - although it is arguable whether we would be able to detect the latter).
Another possibility is that from any point in time there may be infinite possible pasts (just as there are infinite possible futures), such that the singular historical timeline that we imagine ourselves having is essentially a needle in a haystack that would be very hard to get to.  This could protect us from getting time-travelled-into.  That would certainly be funny if time travel were ever invented.  You might not travel into the past that you wanted.  In fact, you would be very very unlikely to...