The only constant I've observed is that the non-FS properties have smaller holds than the FS brands. Obviously because there's more stuff you can charge to your room at a FS.

When I've been on a long trip and the holds start becoming an issue, I've been able to call my bank, explain what's going on and get them to free up some of my available funds. I've never paid attention to the difference between North America and Europe, but I suspect that indeed it does take longer than the normal three business days for holds from there to come off.

For me personally, I find some of the car rental places holds to be a bigger problem than the hotels. Then there's the matter of the $100 that some of the gas stations in Canada like to tack on. That $20 "top off" on the way back to the airport that nicks your card for $100. Put that on top of the previous day's $100 at the gas station, plus the 40% rental car hold, the hotel holds, and....well...you get the idea.....

Or....you could always use the ol' Amex!