Script to detect player moving offmap

want to create something to warn me of players offmap

something along the lines of

_posxplayer = getpos _player select 0
_posyplayer = getpos _player select 1

if ((_posxplayer < 0) || (_posyplayer < 0))
{
_message = format["%1 left the playable map!,_player];
_loc_message = format["%1 left the playable map at %2, %3!,_player, _posxplayer, posyplayer];

diag_log _loc_message;
[nil, nil, rspawn, [_player, _message], { (_this select 0) globalChat (_this select 1) }] call RE;
}

can anyone spot check this logic for me?

also, in MP would this sort of calculation crush performance? maybe set it on a

sleep 10;