Lmao I nearly murdered a mate who tried to steal mines from my bike.
As long as the valves are ok no air will escape. Valve caps aren't air tight.
They just stop beggers lettin your tyres down.
I'm sure they do stop people letting your tyres down as easily but if i am not mistaken, they are to stop all the road crud gathering inside the valve. The clue is in the title, 'dust cap'
Not to worry valves are very cheap also, missus dad owns a tyre shop. Ive not had dustcaps for nearly 3 years and have had no issues yet. The car doesn't get dirty enough to build up crap in them. Doesn't get used in winter either so no drama