Currently, all players and bases are subjected to purges according to server settings. On official servers, this means there are only 4-6 purges per day per server, spread out between all players/clans, both active and inactive, online and offline, who have reached the purge threshold. For leveling players this is positive because it gives them time to build up their bases, but for endgame players, some have had few or no purges even if they have been playing since launch.
It would be useful if it was possible for servers to define a second set of purge options that would specifically only apply to players who opted in that could occur at other times. E.g. a server sets mandatory purges from 6-10pm with 0+ players online, but it allows opt-in purges 24/7 with 0+ players online.
The mechanic I would suggest for the opting-in would be an expensive, buildable structures - enormous beacon pyres, huge banners of provocation, large ornate statues depicting the hubris-filled builder, etc. made of corrupted stone, precious metals, high-end monster heads/bones/meat, obsidian, star metal, etc. In RP terms, it would essentially be something ostentatious or defiant to thumb the builder’s nose at would-be purgers. It could be something that lasted until destroyed, or it could deteriorate and need rebuilt. In either case, the idea would be that only bases with opt-in provocative structures would be eligible purge targets during the opt-in purge windows (while everyone would remain possible targets during normal windows).
This would allow people on PvE servers who primarily want to play the game as a building game (or PvP players who don’t want to deal with purges interrupting their wars) to continue to do so, but let endgame players who otherwise may be running out of things to do have more opportunities to defend against purges.