How do people line up their robots for autonomous. we currently use a laser mounted to the centre of the robot (which is removed before the start of the match). We are wondering how other people do it other than just looking. Maybe with ultrasonics or something.
Metal bars can be made into a jig to square your robot into place. It seems pretty accurate but I’d imagine mounting a laser would be more accurate horizontally because you don’t really have to eyeball it. Also you can probably have a crosshair on your robot to let you aim easlily, too.
There are several ways to do it. 
The backing of my flywheel is a c channel and there’s those triangle notches cut out, i line that up with a center standoff in the front of my fw and the centre post of the net. I’ve never missed on the horizontal axis from the back.
We just use a laser, while the other drive team members help to spot by making sure the robot appears to be lined up properly.
we just eye it. It has worked thus far
My eye isn’t as good as yours.
We used LEGO jigs at worlds last year. We had two jigs - red and blue. They were clear dividers with tiles edges marked by a Sharpie and some LEGO bricks to connect to the robot. Of course, with corresponding colors 
The only problem was that the cubes didn’t slide on the floor at all, so our highest was a 6 point autonomous. At least we learned that anti-static spray makes tiles sticky 
We’ve been told at competitions that we can’t use jigs to line our robot up. Could someone clarify the rule?
we use jigs
We use a laser site, it has improved our auton accuracy by a lot :).
I’m sure that it’s the same thing as using a laser pointer - you remove it, so it shouldn’t matter.
Also, it has the Karthik Seal of Approval on it: https://vexforum.com/t/answered-legality-of-starting-tile-alignment-jigs/30246/1
Jigs are perfectly legal. This is asked every year in the Q&A and Karthik always says as long as you do it in a timely fashion it is fine.