lm_paypal_subscriptions_can_subscribe($subid) always returns true... and issues an error message about line 677 in file lm_paypal_subscriptions.module

function lm_paypal_subscriptions_user_subscribed($subscription, $account = NULL) {
global $user;
static $cache = array();
$subid = $subscription->subid;

The error is created because $subscription is sent in as a string not an object (as per the documentation for lm_paypal_subscriptions_can_subscribe($subid) example)

Changing to: "$subid = $subscription;" fixes the error and returns the proper results if the user is already subscribed or not.