No, the signal indicates whether a given field is for even or odd scanlines. I used plenty of computers and CRTs around that time and not one incorrectly displayed progressive as interlaced.
Neither are most CRT TVs, if you keep feeding them the odd/even field repeatedly. I keep CRT TVs and monitors at home and can easily verify this. The effect is usually dark gaps between the lines or doubled lines (where the corresponding field would otherwise have been drawn). Doubled lines, as in the same as the previous line of the same field, not from the previous field. It's not a particularly obscure subject or uncommon trick, so I don't see why you would keep insisting that it isn't so when any source that possibly could have proven you right, if you were, will prove you wrong.
I'm talking about televisions and similar. You are still simply wrong. Nearly all of the 8-bit and 16-bit consoles and computers that output to CRT default to non-interlaced, without the TV alternating fields.
Look at other responses in this thread to see how interlacing used to be achieved and the flexibility it had.
