Here is the situation- fairly busy afternoon at a class D airport with multiple aircraft in the large runup area and 2 already holding short. You are VFR and so is the guy you end up next to in the run up area. You arrive a bit after him in the run up area but are done with your runup. Question #1 -Do you pull up to the line of aircraft holding short and become third in line? I say yes - the guy next to you could be sorting out any number of issues, changing his mind about any number of things, etc etc. You pull up and are third in line. One aircraft departs, you become #2. The aircraft in front of you departs. As you are pulling up to the hold short line the guy who was next to you in the runup pulls up next to you (the hold short area is very wide) and contacts tower on the radio as he is rolling up. Question #2 - Was this poor form on his part? Spoiler: Tower made him wait and had me depart first.