How to secure an aircraft at a transient parking space?
Tie downs are generally for overnight or longer.   Nobody ties down an airplane for a visit of a few hours unless there is something forecast in that few hours like high winds or thunderstorms.  And if that's the case, you will want move it somewhere on the airport that has unused permanent tie downs or inside a hangar for the duration of the weather event.

Most screw or spike-in grass anchor systems are useless for serious winds and are easily pulled out.  There are several Youtube videos that demonstrate how ineffective they are, with the exception of one system that uses large spade like blades driven into the ground.