Tipping the guide and bus driver

Assuming this is a RS tour, you don’t tip.

I have been on some tours where members have pooled funds (1 or 2 EUR each) to buy a small gift for the guide, but nothing more than that,

NO tipping on Rick Steves tours. It’s one of the things I really like about his tours over other companies’ tours. He pays his tour leaders as the professionals that they are, and arranges appropriate pay and tips for the drivers, local guides, etc. out of the funds that you and the other travelers have already paid to RS Europe.

However if this is not one of Rick's tours, then yes you should tip, providing the service warrants it.

I agree with not tipping if it's a Rick Steves tour. There are also other companies that have tips included in the tour cost so check with the expectations on the tour company site if it's not a Rick tour. For instance, Road Scholar also includes tips in the cost of the tour.

We've been tipping about 20% for our guides depending on our cash situation. I figure the guides are in pretty cash poor at this moment in time.

For most over the road tours in Europe, the suggested tip is the equivalent of 10-15 euros, pounds, etc. Whatever is the local currency.

On some tours, the amount you would tip is already included in the cost of the tour. What you're told is there is no tipping. If you did tip, you'd be tipping double.