Not sure how putting a vent in for a dryer would hurt a warranty--unless you drilled thru a wall stud? Personally, would not vent to the inside, but some have mentioned venting thru the floor.
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired