the server is stationary... in one place.
you can get apps on your desktop that will show you ping/speed etc if you truly wanted to know...
you can go to test sites while in queue... cuz we all know you are on here, facebook, *insert xxx site here *.com , youtube and whatever else while you are waiting for a game...
so why cant you if you are that concerned (or you know you have connection issues ) do that before you go into a game? also they show your ping as you load into game as well. and just because your ping is ok pregame don t mean it cant change while in game. also ping to riots servers is different for everyone based on their connections, traffic, packet loss, etc and not all on riot or their server