Send Friend bot abuse -- non-existent item id PHP notices

[dev-101]

Hi, I was hit by some stupid bot checking constantly my send-friend pages with item IDs which were either removed or disabled, and this was constantly filling my log with notices in hDefines:

Osclass 3.7.4

https: // www . url .com/item/send-friend/ 123

PHP Notice:  Undefined index: fk_i_category_id in oc-includes/osclass/helpers/hDefines.php on line 491
PHP Notice:  Undefined index: pk_i_id in oc-includes/osclass/helpers/hDefines.php on line 497
PHP Notice:  Undefined index: s_city in oc-includes/osclass/helpers/hDefines.php on line 498
PHP Notice:  Undefined index: s_title in oc-includes/osclass/helpers/hDefines.php on line 499

Now, I've dealt with the bot all right, but these notices actually helped me track and discover "the pest", otherwise it would slip my radar.

And, that's why I am undecided if we should fix this or not. I mean, it's easy to fix, but it may be actually useful, assuming we know where to look. Less experienced users will probably fail to identify the problem and may think something is wrong with their setup. A compromise would be to throw custom error in the logs, so we get better insight where/why the notice originated from, so admins don't instantly panic :)