U can try to appeal that. Few summons were issued to my wife
when she parked at " no parking " & " reserved lot " but after
I wrote the appeal, they always waived it as I give that quite a
good reasons.
I think the only problem is that u should know that the free
parking apply to all hdb block is only about 7am to 10pm. If u had
put a coupon that morning , may be they will waive off.