I understand that might sound a bit funny, but… I have sent a card but forgot to write an ID. Is not this against the rules that I send a message to the adressee with an ID number or this can be considered to be unfair and against the rules?
Thanks to all. Have a nice day
Welcome to the forum @Nedoumenie!
Upon registration the receiver is able to request help when an ID is missing or wrong. The postcrossing support is usually able to identify the sender based on country, city, date (via postmark) or any information you wrote on your card that’s also on your profile.
Don’t worry!
Yes, go ahead & send them the ID, that will speed things up & save an admin person a job of looking for it.
It’s one of the reasons I always put my PC name on my cards & ask people sending cards to me to do the same, so this kind of thing can get sorted out more easily.
Yes, send them a message explaining the situation. Tell them when they receive the card without ID they can register it with the ID you give them. Make sure that it’s clear you don’t ask for a card to be registered that didn’t arrive.
If the card goes to a country with a longer travel time you can also wait a little before sending the message so there might be less time between the message and the card actually arriving. It might be easier for them to remember and find the message that way.
Hey!
I just forgot to write down the ID on a postcard I’ve already sent.
Should I report this to the admins? Or should I just write a frienfly message to the receipient of the card?
Best wishes to All of you
Andreas
I’d send them a message if you know for sure which card it was with a scan of the card, so they know what to look for Andreas - we all forget the ID sometimes eh?
It happend to me once. Somebody forget the ID and wrote me a small message with the number and a describtion of the card. I registered it as soon as it arrived.
It happens every now and then. I would notify the the person who should get the card and you should be fine. 
Hello @itslovelyhoneymoon ,
Here you will read more information/ help regarding the “forgotten ID”
“Sending postcards”
I forgot to write the Postcard ID on the postcard I sent
Don’t worry, the receiver can still ask for help when they receive your postcard.
If you would like to make their life a little easier, just write them a private message to explain that they will be receiving a postcard without a Postcard ID, and include the Postcard ID in the message. Please note that the recipient can only register your postcard when it arrives in their mailbox.
I recommend that you just wait.
When your card arrives, the recipient can contact the support and ask for the ID.
Only if the card has been on the way much longer than normal you should ask the recipient about it.
Thank you all for your replies.
@Bille I’m having a postcard travelling to Brazil for 4 months now. Do you consider this as normal?
Best wishes,
Andreas
Cards to Brazil are often for a very long time on the way, but I think 4 months is not necessarily normal.
Is that the card without ID?
Then it’s time to ask the recipient for it.
I would just wait as you say, but so many people seems to not know about the possibility to ask for missing IDs 
Well…… I was so excited about sending World Postcard Day cards today that my cards went out without ID’s written in them……what is the best thing to do when this happens???
I sometimes receive postcards without ID.
But it’s okay 
So I think you should wait for “hurray” mail or send PM to the user.
Don’t worry 
As I wrote before …
Hi. Just write an card ID to the receiver in private message 
I made this experience, too.
One time a User didn’t see the ID (since then I use different colours) and once it seems I really forgot it.
Both users I asked and both didn’t know about the possiblity to search for help.
Also I read it very often in profiles that people ask sender xy to get in touch because of missing ID.