The forum has added the strikethough option to the message box. You can select it from the menu (see arrow in pic) or custom add the bbcode using s and /s in brackets for the text you want the strikethrough
This
Results in this
Forest River Forum members are the best greatest!
__________________
2011 Flagstaff 831 RLBSS
A 72 hour hold in a psych unit is beginning to intrigue me as a potential vacation opportunity.