Often sellers limit their items for sale to their home country. However, when a personal email is sent, they often agree to send the item abroad as well. Recently I used myibidder to snipe at such an item, however the snipe was not done because "seller has restriction on shipping addresses". This was unfortunate, the warning came only at the time of the snipe (too late for a regular bid), but I would prefer that myibidder would not act so "clever", or at least an option was there to overrule this behaviour.

If seller set a restriction to block bidders they don't want, there is no way to override it.
You can't go around it until seller will either remove the block or add you to the exception list of allowed bidders.

When not sure, please place a minimum manual bid first. If your manual bid would not work, your snipe will not work as well.

Thanks. I had the (probably wrong) impression that it was myibidder trying to be clever, but you may be quite right if it was the bidder who did it. I will follow your suggestion.