Past Tense in Future Event

[phenux]

I understand that the present and present perfect tense can be used to talk about future events, but I am greatly confused as to why it is also acceptable to use the past tense.


Please explain the following sentences that I came across:

If you found this note then this towel has not been washed.

Once the plane arrived, the flight attendants will tell us to unbuckle our seat belts.

 

[5jj]

Both sentences are unnatural. Where did you come across them?

 

[phenux]

Whoops I got the first sentence wrong. It took me awhile, but I managed to dig through Reddit archive and found the 4 old months thread
http://www.reddit.com/r/funny/comments/1htkcb/my_mom_is_at_a_hotel_and_found_this_note_in_her/

The message is:

If you found this it wasn't washed! My butt was all over it! Thank you!

The second one, I got it from a NPR's interview which at the moment I am unable to find the transcript.

Thank you for your lightning-fast response, 5jj.

 

[Barb_D]

Well, isn't that first one a lovely sentiment.

Sometimes in movies or books, you have a situation where the person had disappeared, the lawyer has instructions to deliver a certain video tape (or letter) if the person is missing, and the videotape/letter begins "If you're watching/reading this, and my lawyer has followed my instructions, I am missing." In other words, if something is happening now, something must have happened (or not happened) in the past.

I guess if I write on a towel and you can read it later, it hasn't been washed, because the writing would have been washed away.

The second one should be "arrives" not "arrived."

 

[phenux]

# I wrote the below sentences after reading "Help! I can't find my post!" thread.
# I think this post is more organized and expresses my thought clearer than my previous post. If my previous post does get through moderator approval please skip it and read this one instead. I am extremely sorry for the inconvenience.

Sorry if this is a repeat post because the previous reply that I posted was waiting for moderator approval; I think it got denied because the moderators' respond time is usually fast, and it linked to another site before being checked with moderator which violated the Spamming Rule. I want to apologize for skimming the Forum Rules too fast.

Below is my previous post with the link being omitted:

Whoops I got the first sentence wrong. It took me awhile but I managed to dig through Reddit Archive and found the old thread where I came across it. However, I was unable to find source for the second sentence, but I found another similar sentence related to the topic.

Snapshot of a note that was found in a hotel's robe/towel:

If you found this it wasn't washed! My butt was all over it! Thank you!

Could it be written as:

If you find this it hasn't been washed! My butt was all over it! Thank you!
If you find this it isn't washed! My butt has been all over it! Thank you!

Second sentence found in Reddit Science:

I would not be surprised if it was found that sleep deprivation was the root cause to many of today's society's trending diseases.
vs
I will not be surprised if it is found that sleep deprivation is the root cause to many of today's society's trending diseases.

 

[Barb_D]

Honestly, this sentence is just so gross.

You can say "it hasn't been washed" because the possibility for washing still exists.
You cannot say "has been all over it" because the opportunity for butt smearing is now past.