I don't get the reason why you think it is unsafe. It is not the jack that is providing the safety factor but the jackstand which is stopping the control arm from dropping down??? Are you afraid that gravity is going to fail and the car fly up into the air causing the spring to decompress? The shock is not carrying the load in the picture.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13