Yes, early days of slideouts had issues that often needed supports.
Newer slide technology has eliminated the need for these and often will void warranty if the owners does use them and it causes problems.
Dan-Retired California Firefighter/EMT
and Zoe the Wonder Dog(R.I.P.)
2016 PrimeTime TracerAIR 255, pushing a 2014 Ford F150 SCREW XTR 4x4 3.5 Ecoboost w/Max Tow Package