peteblue
Welcome back Wayne
Spare parts and ammo coming from German manufactures, you can't just send military equipment in isolation.
Not to mention contract and possibility for future sales, not just military, German companies got big sway in Polish economy, basically cheap labor for German firms all over Eastern Europe.
Poland used it for PR (and for internal politics by ruling PIS party), but i utterly doubt they gonna do anything without German consent.
Germany is EU, thats exactly how are they seen here.
Also as comment above says, nobody wants to see their precious toys destroyed, just look at Saudi and Iraqi Abrams popped by Houthis and ISIL (though i read Ukrainian military love German Gepard AA tanks, apparently they top their wishlist)
Trust me I do understand the mechanics of arms sales. However I also understand that German industry will not give up future sales of main units or spares just because the current Chancellor is weak and pathetic. If Poland or any other EU country sent German equipment to Ukraine without permission Germany would be politically positioned between a rock and a hard place, with its profitable industries having a few words with the government……