Btw, just get a magfloat. They have them for acrylic and glass tanks in different shapes and sizes. there are also other ways of keeping algae and sediment off your tank walls. Look into it!
it's always the same case of a perception of invincibility. everyone always thinks it's(pleco sucking slime off the gar) only going to happen to someone else. unfortunately, it's not the case, and unfortunately, it only takes one attack for to cause potentially fatal damage. if you care about your gar at all or if you consider yourself a responsible fish keeper of any sorts, you'd remove the pleco right away.