Exposed brass caps disappear quickly in frequented areas due to memorabilia collectors (I've seen marked caps go for $75 on Ebay) and metal scavengers stealing them.?ÿ Exposed quality plastic caps are UV resistant and worthless for resale *but* not fire resistant. Aluminum caps are equivalent to brass caps except their melting point is 650?øF so in a hot fire they may melt where a brass cap survives.
Call me curmudgeon but my typical rebar monument is buried several tenths below grade and is memorialized by a brass tag with my LS# affixed to the rebar a couple inches from the top with Monel wire.?ÿ Lasts many decades and a Schonstedt will ring like a bell when searched for by a surveyor and the rebar will be evident for centuries.
Monuments should be shielded from public view & mowers, etc., to prevent accidental or mischievous activities.?ÿ Sure, I'll stake them with some flagging for the the client's elucidation but the stakes are gone soon thereafter.?ÿ Sticking up a monument proud invites liability; much better to bury it so only a journeyman or better surveyor can recover it.