I thought about this a lot of times when I used to play Futures and Challengers. A lot of time I played against players who had lower ranking than me and I thought I was gonna be the favourite but then they turned out to be "future-pros" with 1900 or 2000 ELO and the gave me 6-1 6-1 like popcorn

But, as djarvik says, unfortunately there is no way to know what the player ELO is before the tournament and, plus, it could change from the time he signs up to the time tournament starts. So I think that things like that could always happen, just like in real tennis when some Kokkinakis or Kyrgios come along, you just have to deal with it and hoping that someone else will face them as long as they are still "fake" noobs.