foot activated hatch or trunk release
 

not a feature on the current a5 ?

This works on my S5 Sportback (Prestige if it makes a difference).

It works on my A5 P+.

Standard on A5 & S5s

Apparently there are a few issues where it won't work like if you turn the car off and walk back to the trunk or if you're getting interference from the other key or some things like that. Look it up in the manual and it explains it better, haha

i didn't experience any problems with the foot activation. its works like a charm normally. other than those rainy days you might need to exaggerate the movement a little.