Booking a hotel for your group – or yourself? Word to the wise: pay extra close attention to the fine print.

As a meeting & event planner, you travel – a lot – so no doubt you’ve already encountered hotel “resort fees”. These fees typically range from $25 to $50 per day, and cover everything from beach umbrellas and lounge chairs to fitness centers and tennis courts – whether you use them or not. Now, imagine you’re booking an average-size group – say, 100 rooms for 4 nights. Even at the low end, that’s an extra $10,000!

And these supplemental fees continue to creep up. According to a new study by New York University hospitality professor Bjorn Hanson, hotels will rake in roughly $2.25 billion in revenue this year from added fees—that’s 6% more than in 2013 and nearly double that of a decade ago

Lately, we’ve been hearing about other fees you might not expect. Here are:

10 hotel fees that are sneaky, surprising, or just plain annoying.

1. Mini-bar – Mini-bar charges are already outrageous, but now, even moving an item in the minibar can trigger a fee. Many hotels bill items to guests’ rooms if sensors in the minibar note they have been removed for more than 60 seconds.

We read about a Las Vegas resort that goes one step further, charging a $25 a day “personal use fee” if a guest puts their own soda or bottled water in the minibar. A guest in need of a mini refrigerator can have one delivered to their room — for an extra $35 a night.

2. Early check-in / late departure – If  you want to an early check-in or late check-out, it’s fairly standard for hotels to charge a $50 penalty or imposed a “day rate “of about 60 percent of the regularly nightly rate. Now, more hotel chains are imposing the full nightly rate.

3. “Urban” Fees – Resort properties are not the only ones cashing in on extra fees.  A $20 per night “Urban Fee” at a hotel in downtown San Francisco includes Internet, local phone calls, newspapers, morning coffee and use of bicycles. Again, you’ll be charged whether or not you avail yourself of these amenities.

4.  Confirmed Bed Type – Prefer two queen beds or one king? A quiet room away from the elevator? That might also cost you – some hotels in Las Vegas charge $30 to guarantee room preference or bed type.

5. Towel Card Charge: Many resorts provide towel cards at check-in that you exchange for a towel at the pool or beach. If you don’t return the card at check-out, expect to see a charge as high as $25.

6. Fitness Center – Want to work out during your meeting or business trip? It will cost you. If not included in the resort fee, expect to pay anywhere from $10 – $40 a visit.

7. Audio/Visual – AV fees can really add up. Meeting planners who want to bring in their own AV company are complaining about hotels that charge a fee for not using that property’s in-house service (much like a restaurant charging a corkage fee).

8. Valet Parking – Some hotels offer self parking (for a fee), but many downtown hotels charge up to $40 a day for mandatory valet parking – tip not included!

9.  Room Service – Figure on a charge of up to $20 for a simple continental breakfast (pastries, coffee, juice) from room service. Delivery charges and 18 – 20% gratuity are usually added on as well.

10. Tax on Service Charge – Our staff reported a hotel that added 22% service to F&B charges – and then taxed the service charge! Thank goodness meals are included on a cruise.

To be fair, not all hotels are guilty of these sneaky “hidden fees”, and many disclose resort fees at the time of booking. But be aware and check your hotel bill or group contract carefully for miscellaneous charges. Demand transparency, especially in regard to resort fees. Better to negotiate these items in advance than dispute them at checkout or while reconciling your group account back in the office.

Want to trim your costs and avoid the whole issue of “hidden fees” ?

Book a cruise! Save big with these budget items included in your cruise rate: Meals in main dining room as well as casual dining and room service, entertainment and shipboard activities (including sports and fitness center), meeting space and AV equipment.

Of course, additional charges may appear on your shipboard account, but these are transparent and optional, such as surcharges in specialty restaurants, spa services, alcoholic beverages, some fitness/enrichment classes, shore excursions, Internet access, and casino gaming. No big surprises here.