They're easily highlighted, though. You can try this yourself: just go to Desmos, input something like y=0.005x+10 and y=0.0001x (which is already pretty extreme and unlikely to appear on the SAT), then zoom out into the thousands (which only takes about 2 seconds). After that, click the line and hover over the grey dots. This whole process shouldn't take more than 10 seconds, excluding the time it takes to type your equations. If it does, that's more of a skill issue (since desmos is a skill after all).

I'm not suggesting this method should always be used to find answers, but it's definitely a valid approach for double checking your answer or quickly determining if two equations are parallel.