Poor internet security

[puggit]

Just tried to log in to a major airline's members' pages - I was having trouble logging in, so selected to have a new password emailed to me.

After requesting the new password I went straight to my webmail, and there it was

Went back to my browser and there was a short message on the screen - and I was logged in

Now my question is - what method do I go about to warn them, while reaping the benefits (ie free upgrades, airmiles etc!)

[polus]

Be careful how you warn them, it may be taken the wrong way...